Surgical tensor configured to distribute loading through at least two pivot points

ABSTRACT

A surgical apparatus configured to be placed in the musculoskeletal system to precisely separate a first bone from a second bone. The surgical apparatus has one or more sensors to measure one or more parameters and supports one or more bone cuts for installing a prosthetic component. The surgical apparatus has at least one distraction mechanism configured to increase or decrease a height between a first support structure and a second support structure. A tilt mechanism comprises the at least one distraction mechanism. The tilt mechanism couples through a first pivot point and a second pivot point and adjusts a tilt of the second support structure relative to the first support structure. In one embodiment, loading applied to the second support structure is distributed between the first pivot point and the second pivot point during operation of the surgical apparatus.

FIELD

The present disclosure relates generally to orthopedic medical devices,and more specifically to devices that generate quantitative measurementdata in real-time.

BACKGROUND

The skeletal system of a mammal is subject to variations among species.Further changes can occur due to environmental factors, degradationthrough use, and aging. An orthopedic joint of the skeletal systemtypically comprises two or more bones that move in relation to oneanother. Movement is enabled by muscle tissue and tendons attached tothe skeletal system of the joint. Ligaments hold and stabilize the oneor more joint bones positionally. Cartilage is a wear surface thatprevents bone-to-bone contact, distributes load, and lowers friction.

There has been substantial growth in the repair of the human skeletalsystem. In general, prosthetic orthopedic joints have evolved usinginformation from simulations, mechanical prototypes, and patient datathat is collected and used to initiate improved designs. Similarly, thetools being used for orthopedic surgery have been refined over the yearsbut have not changed substantially. Thus, the basic procedure forreplacement of an orthopedic joint has been standardized to meet thegeneral needs of a wide distribution of the population. Although thetools, procedure, and artificial joint meet a general need, eachreplacement procedure is subject to significant variation from patientto patient. The correction of these individual variations relies on theskill of the surgeon to adapt and fit the replacement joint using theavailable tools to the specific circumstance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an orthopedic measurement system generatingquantitative measurement data to support installation of a prostheticcomponent in accordance with an example embodiment;

FIG. 2 is an illustration of the orthopedic measurement systemdistracting a knee joint of a leg in accordance with an exampleembodiment;

FIG. 3 illustrates the cover, the module, and the distractor inaccordance with an example embodiment;

FIG. 4 illustrates a cover on the module configured having ananterior-posterior (A-P) slope of zero in accordance with an exampleembodiment;

FIG. 5 illustrates a cover on the module configured having ananterior-posterior (A-P) slope of 2 degrees in accordance with anexample embodiment;

FIG. 6 illustrates a cover on the module configured having ananterior-posterior (A-P) slope of 4 degrees in accordance with anexample embodiment;

FIG. 7 illustrates a cover on the module configured to interface withnatural condyles of the femur in accordance with an example embodiment;

FIG. 8 illustrates a cover having a support structure on the moduleconfigured to interface with a femoral prosthetic component inaccordance with an example embodiment;

FIG. 9 illustrates a cover on the module configured to interface with afemoral prosthetic component having a support structure coupled to afemur in accordance with an example embodiment;

FIG. 10A illustrates the frame and a frame retaining support structurein accordance with an example embodiment;

FIG. 10B illustrates the frame coupled to the frame retaining supportstructure in accordance with an example embodiment;

FIG. 11 illustrates different frame sizes in accordance with an exampleembodiment;

FIG. 12A illustrates the moving support structure disengaged from theM-L tilt mechanism in accordance with an example embodiment;

FIG. 12B illustrates the moving support structure coupled to M-L tiltmechanism in accordance with an example embodiment;

FIG. 13 is an illustration of the M-L tilt mechanism in accordance withan example embodiment;

FIG. 14 is an illustration of the distraction mechanism in accordancewith an example embodiment;

FIG. 15 is a block diagram of electronic circuitry in the distractor ofFIG. 1 or the module of FIG. 1 in accordance with an example embodiment;

FIG. 16 is an illustration of a magnetic angle sensor coupled to the M-Ltilt mechanism in accordance with an example embodiment;

FIG. 17 is an illustration of the magnetic angle sensor in thedistractor in accordance with an example embodiment;

FIG. 18 is an illustration of the moving support structure tiltinglaterally in accordance with an example embodiment;

FIG. 19 is an illustration of a magnetic distance sensor in thedistractor in accordance with an example embodiment;

FIG. 20 is an illustration of the display of the computer as shown inFIG. 1 in accordance with an example embodiment;

FIG. 21 is an illustration of a top view of the module in accordancewith an example embodiment;

FIG. 22 is an illustration of the module with a portion of an enclosureremoved in accordance with an example embodiment;

FIG. 23 is an exploded view of an insert prosthetic component inaccordance with an example embodiment;

FIG. 24 is an anterior view of the insert installed on a tibialprosthetic component in accordance with an example embodiment;

FIG. 25 is a side view of the insert installed on the tibial prostheticcomponent in accordance with an example embodiment;

FIG. 26 illustrates a step in a knee joint installation procedure inaccordance with an example embodiment;

FIG. 27 illustrates a step of placing the distractor in the knee jointof the leg in accordance with an example embodiment;

FIG. 28 illustrates a step of displaying the distraction distance dataand the M-L tilt angle on a display in real-time in accordance with anexample embodiment;

FIG. 29 illustrates a step of increasing the distraction distance untila predetermined loading is achieved in accordance with an exampleembodiment;

FIG. 30 illustrates a step of reviewing the position of load, the loadmagnitude, M-L tilt angle, and the distraction distance on the displayas the distraction distance of the distractor is increased in accordancewith an example embodiment;

FIG. 31 illustrates a step of reviewing an x-ray in accordance with anexample embodiment;

FIG. 32 illustrates an equalizing step where the M-L angle of the movingsupport structure is adjusted in accordance with an example embodiment;

FIG. 33 illustrates a step of monitoring equalization of the femur onthe display in accordance of an example embodiment;

FIG. 34 illustrates a step of drilling guide holes in the femur inaccordance with an example embodiment;

FIG. 35 illustrates a step of removing a drill guide and drill guideholder from the distractor in accordance with an example embodiment;

FIG. 36 illustrates a step of reducing the distraction distance of thedistractor and placing the leg in flexion in accordance with an exampleembodiment;

FIG. 37 illustrates a step of adjusting the distraction distance whilethe leg is in flexion in accordance with an example embodiment;

FIG. 38 illustrates a step of equalizing the medial gap and the lateralgap with the leg in flexion in accordance with an example embodiment;

FIG. 39 illustrates a step of placing a sizer on the distractor tosupport selection of a femoral prosthetic component in accordance withan example embodiment;

FIG. 40 illustrates a step of coupling a femur coupler to the femur withthe leg in flexion in accordance with an example embodiment;

FIG. 41 illustrates a step of providing a plurality of sizers to supportselection of the femoral prosthetic component;

FIG. 42 illustrates a step of drilling one or more holes in the distalend of the femur in flexion in accordance with an example embodiment;

and

FIG. 43 illustrates one or more holes drilled in the distal end of thefemur in accordance with an example embodiment;

FIG. 44 is an illustration of an alternate embodiment of a distractor inaccordance with an example embodiment;

FIG. 45 is an illustration of the alternate embodiment of the distractorwith a transparent housing to illustrate components therein inaccordance with an example embodiment;

FIG. 46 illustrates a step in a knee joint installation procedurerelated to the alternate embodiment of the distractor shown in FIG. 44in accordance with an example embodiment;

FIG. 47 illustrates a step in the knee joint installation procedurerelated to the alternate embodiment of the distractor wherein the knobis rotated counter clockwise in accordance with an example embodiment;

FIG. 48 illustrates a step in the knee joint installation procedurerelated to the alternate embodiment of the distractor coupling to thefemur in accordance with an example embodiment;

FIG. 49 illustrates the step in a knee joint installation procedurerelated to the alternate embodiment of the distractor where the lateralplate and the medial plate contact the femur in accordance with anexample embodiment;

FIG. 50 illustrates a step in the knee joint installation procedurerelated to the alternate embodiment of the distractor where equalizationof the medial gap and the lateral gap occurs in accordance with anexample embodiment;

FIG. 51 depicts an exemplary diagrammatic representation of a machine inthe form of a system in accordance of an example embodiment;

FIG. 52 is an illustration of a communication network for measurementand reporting in accordance with an exemplary embodiment;

FIG. 53 illustrates a surgical apparatus having three distractingmechanisms configured to distract a knee joint in accordance with anexample embodiment;

FIG. 54 is an exploded view of the surgical apparatus in accordance withan example embodiment;

FIG. 55 is an illustration of the surgical apparatus showing bottomsurfaces of the femoral support and the tibial support in accordancewith an example embodiment;

FIG. 56A is an illustration of a plurality of femoral supports inaccordance with an example embodiment;

FIG. 56B illustrates femoral support 5008 in accordance with an exampleembodiment;

FIG. 56C illustrates the module being inserted into the femoral supportin accordance with an example embodiment;

FIG. 57 is an illustration of a first cover and a second cover prior tocoupling to the module in accordance with an example embodiment;

FIG. 58 is an illustration of the femoral support being coupled to themedial support structure and the lateral support structure in accordancewith an example embodiment;

FIG. 59A is an illustration of the surgical apparatus showing the tibialsupport being coupled to the tibial support holder in accordance with anexample embodiment;

FIG. 59B is an illustration of the arm of the tibial support positionedin relation to the retaining clip prior to coupling in accordance withan example embodiment;

FIG. 59C is an illustration showing the clip being pressed to allowclearance for the arm of the tibial support to allow movement past thesupport structure of the tibial support holder in accordance with anexample embodiment;

FIG. 59D is an illustration showing the arm of the tibial support beingsupported by a support ledge of the support structure of the tibialsupport structure in accordance with an example embodiment;

FIG. 60 is a top view of the surgical apparatus having an offset for aright knee joint and an offset for a left knee joint in accordance withan example embodiment;

FIG. 61 is an illustration of a first distraction mechanism of thesurgical apparatus in accordance with an example embodiment;

FIG. 62 is an illustration of a second distraction mechanism of thesurgical apparatus in accordance with an example embodiment;

FIG. 63 is an illustration of a third distraction mechanism of thesurgical apparatus in accordance with an example embodiment;

FIG. 64 is an illustration of a surgical apparatus in accordance with anexample embodiment;

FIG. 65 is a top view of an offset of the surgical apparatus for use ina left knee in accordance with an example embodiment;

FIG. 66 is a top view of an offset of the surgical apparatus for use ina right knee in accordance with an example embodiment;

FIG. 67 is an illustration of the surgical apparatus with a medial and alateral compartment height in a minimum height position in accordancewith an example embodiment;

FIG. 68 is an illustration of the surgical apparatus changing a heightof the medial and lateral compartments simultaneously in accordance withan example embodiment;

FIG. 69 is an illustration of the surgical apparatus changing a heightof the medial compartment in accordance with an example embodiment; and

FIG. 70 is an illustration of the surgical apparatus changing a heightof the lateral compartment in accordance with an example embodiment.

DETAILED DESCRIPTION

The following description of exemplary embodiment(s) is merelyillustrative in nature and is in no way intended to limit the invention,its application, or uses.

Processes, techniques, apparatus, and materials as known by one ofordinary skill in the art may not be discussed in detail but areintended to be part of the enabling description where appropriate.

While the specification concludes with claims defining the features ofthe invention that are regarded as novel, it is believed that theinvention will be better understood from a consideration of thefollowing description in conjunction with the drawing figures, in whichlike reference numerals are carried forward.

The example embodiments shown herein below of the surgical apparatus areillustrative only and do not limit use for other parts of a body. Thesurgical apparatus can be used to measure, distract, align, cut, andsupport installation of prosthetic components to the musculoskeletalsystem. The surgical apparatus can be used on the knee, hip, ankle,spine, shoulder, hand, wrist, foot, fingers, toes, and other areas ofthe musculoskeletal system. In general, the principles disclosed hereinare meant to be adapted for use in other locations of themusculoskeletal system. The following description of embodiment(s) ismerely illustrative in nature and is in no way intended to limit theinvention, its application, or uses.

For simplicity and clarity of the illustration(s), elements in thefigures are not necessarily to scale, are only schematic and arenon-limiting, and the same reference numbers in different figures denotethe same elements, unless stated otherwise. Additionally, descriptionsand details of well-known steps and elements are omitted for simplicityof the description. Notice that once an item is defined in one figure,it may not be discussed or further defined in the following figures.

The terms “first”, “second”, “third” and the like in the Claims or/andin the Detailed Description are used for distinguishing between similarelements and not necessarily for describing a sequence, eithertemporally, spatially, in ranking or in any other manner. It is to beunderstood that the terms so used are interchangeable under appropriatecircumstances and that the embodiments described herein are capable ofoperation in other sequences than described or illustrated herein.

Processes, techniques, apparatus, and materials as known by one ofordinary skill in the art may not be discussed in detail but areintended to be part of the enabling description where appropriate.

The orientation of the x, y, and z-axes of rectangular Cartesiancoordinates is assumed to be such that the x and y axes define a planeat a given location, and the z-axis is normal to the x-y plane. The axesof rotations about the Cartesian axes of the device are defined as yaw,pitch and roll. With the orientation of the Cartesian coordinatesdefined in this paragraph, the yaw axis of rotation is the z-axisthrough body of the device. Pitch changes the orientation of alongitudinal axis of the device. Roll is rotation about the longitudinalaxis of the device. The orientation of the X, Y, Z axes of rectangularCartesian coordinates is selected to facilitate graphical display oncomputer screens having the orientation that the user will be able torelate to most easily. Therefore the image of the device moves upward onthe computer display whenever the device itself moves upward for exampleaway from the surface of the earth. The same applies to movements to theleft or right.

Although inertial sensors are provided as enabling examples in thedescription of embodiments, any tracking device (e.g., a GPS chip,acoustical ranging, accelerometer, magnetometer, gyroscope,inclinometers, or MEMs devices) can be used within the scope of theembodiments described.

At least one embodiment is directed to a kinetic orthopedic measurementsystem to aid a surgeon in determining real time alignment, range ofmotion, loading, impingement, and contact point of orthopedic implants.Although the system is generic to any orthopedic surgery (e.g., spinal,shoulder, knee, hip, ankle, wrist, finger, toe, bone, musculoskeletal,etc.) the following examples deal with orthopedic surgery as anon-limiting example of an embodiment of the invention.

The non-limiting embodiment described herein is related to quantitativemeasurement based orthopedic surgery and referred to herein as thekinetic system. The kinetic system includes a sensor system thatprovides quantitative measurement data and feedback that can be providedvisually, audibly, or haptically to a surgeon or surgical team. Thekinetic system provides the surgeon real-time dynamic data regardingforce, pressure, or loading on the joint, contact and congruency througha full range of motion, and information regarding impingement.

In general, kinetics is the study of the effect of forces upon themotion of a body or system of bodies. Disclosed herein is a system forkinetic assessment of the musculoskeletal system. The kinetic system canbe for the installation of prosthetic components or for monitoring andassessment of permanently installed components to the musculoskeletalsystem. For example, installation of a prosthetic component can requireone or more bone surface to be prepared to receive a device orcomponent. The kinetic system is designed to take quantitativemeasurements of at least the load, position of load, or alignment withthe forces being applied to the joint similar to that of a final jointinstallation. The sensored measurement components are designed to allowligaments, tissue, and bone to be in place while the quantitativemeasurement data is taken. This is significant because the bone cutstake into account the kinetic forces where a kinematic assessment andsubsequent bone cuts could be substantial changed from an alignment,load, and position of load once the joint is reassembled.

A prosthetic joint installation can benefit from quantitativemeasurement data in conjunction with subjective feedback of theprosthetic joint to the surgeon. The quantitative measurements can beused to determine adjustments to bone, prosthetic components, or tissueprior to final installation. Permanent sensors can also be housed infinal prosthetic components to provide periodic data related to thestatus of the implant. Data collected intra-operatively and long termcan be used to determine parameter ranges for surgical installation andto improve future prosthetic components. The physical parameter orparameters of interest can include, but are not limited to, measurementof alignment, load, force, pressure, position, displacement, density,viscosity, pH, spurious accelerations, color, movement, particulatematter, structural integrity, and localized temperature. Often, severalmeasured parameters are used to make a quantitative assessment. Agraphical user interface can support assimilation of measurement data.Parameters can be evaluated relative to orientation, alignment,direction, displacement, or position as well as movement, rotation, oracceleration along an axis or combination of axes by wireless sensingmodules or devices positioned on or within a body, instrument,appliance, vehicle, equipment, or other physical system.

At least one embodiment is directed to a system for adjusting ormonitoring a contact position of a musculoskeletal joint for stabilitycomprising: a prosthetic component configured to rotate after beingcoupled to a bone; a sensored prosthesis having an articular surfacewhere the sensored prosthesis is configured to couple to the prostheticcomponent, where the sensored prosthesis has a plurality of load sensorscoupled to the articular surface and a position measurement systemconfigured to measure position, slope, rotation, or trajectory, and aremote system configured to wirelessly receive quantitative measurementdata from the sensored prosthesis where the remote system is configuredto display the articular surface, where the remote system is configuredto display position of applied load to the articular surface, and wherethe remote system is configured to report impingement as themusculoskeletal joint is moved through a range of motion (ROM).

FIG. 1 is an illustration of an orthopedic measurement system 1generating quantitative measurement data to support installation of aprosthetic component in accordance with an example embodiment.Orthopedic measurement system 1 comprises a distractor 10, a module 32,and a computer 12. Distractor 10 can also be called a surgicalapparatus, tensor, device, or tool. Distractor 10 is not limited todistraction but can perform or support other functions such asalignment, bone cuts, and parameter measurement to name but a few.Distractor 10 includes at least one sensor configured to generatequantitative measurement data. Similarly, module 32 includes at leastone sensor configured to generate quantitative measurement data.Distractor 10 and module 32 each includes electronic circuitryconfigured to control a measurement process and transmit measurementdata to computer 12. Computer 12 includes a display 14 configured todisplay the quantitative measurement data received from distractor 10and module 32, analyze the measurement data, provide visual, haptic, oraudible feedback related to the measurement data. In general, a workflowof the surgery is provided on computer 12 based on preliminaryinformation, medical data, and measurement data that can include X-Rays,MRI, and CT scan information to support an optimal installation. It iscontemplated that measurement data from the distractor, surgicalapparatus, or tool as described herein will update the plan and thesoftware in the computer can suggest changes based on the quantitativemeasurement data. In one embodiment, any changes suggested by thecomputer and software have to be approved by the surgeon or surgicalteam performing the operation.

Distractor 10 is configured to be inserted into a joint of themusculoskeletal system. The joint can comprise natural bones or one ormore prosthetic components. In one embodiment, distractor 10 can changea height on a first side or a second side of the device within the jointor musculoskeletal system. Distractor 10 is not limited to distractingthe first and second sides but can be adapted to distract more than twosides in combination or alone. Distractor 10 is configured to beoperated by a user such as a surgeon or can be operated by a robot. Inone embodiment, distractor 10 is configured to provide quantitativemeasurement data that supports at least one bone cut on the joint.Distractor 10 includes a distraction mechanism that is configured tochange the height on the first side and the second side by equal amount.Distractor 10 further includes a tilt mechanism that is configured tochange height on the first and second sides by tilting. In oneembodiment, distractor 10 is configured to support alignment, adjustload magnitude, and load balance between the first side and the secondside prior to installation of a prosthetic component. The at least onebone cut supported by the distractor 10 incorporates alignment, loadmagnitudes and balance to the prosthetic component installation usingquantitative measurement data thereby eliminating modification to themusculoskeletal system or prosthetic components after installation ofthe prosthetic components. In one embodiment, a distraction distance ofdistractor 10 and an M-L tilt angle of moving support structure 30 ismeasured and displayed on display 14 of computer 12.

Distractor 10 comprises a housing 20, distraction mechanism 24,medial-lateral (M-L) tilt mechanism 22, a fixed position supportstructure 28, and a moving support structure 30. In one embodiment, M-Ltilt mechanism 22 couples between distraction mechanism 24 and fixedposition support structure 28. Housing 20 partially houses distractionmechanism 24. A knob 26 or handle couples to distraction mechanism 24 toallow a user to increase or decrease a distraction distance ofdistractor 10. Housing 20 retains distraction mechanism 24 and supportsmovement of distraction mechanism 24 in a predetermined directionrelative to fixed position support structure 28. In the exampleembodiment, fixed position support structure 28 couples to housing 20and distraction mechanism 28 and moves perpendicular to a bottom surface34 of fixed support structure 28. Moving support structure 30 couples toM-L tilt mechanism 22. Distraction mechanism 24 couples to M-L tiltmechanism 22 and is configured to raise or lower M-L tilt mechanism 22and moving support structure 30 relative to fixed support structure 28.A distraction mechanism lock 38 is configured to lock distractionmechanism 24 from moving thereby holding a distance between movingsupport structure 30 and fixed support structure 28 constant.

M-L tilt mechanism 22 is configured to medially or laterally tilt movingsupport structure 30. A key or knob couples to M-L tilt mechanism 22 tochange the M-L tilt. M-L tilt mechanism 22 can be disengaged from movingsupport structure 30 such that moving support structure 30 can freelytilt medially or laterally depending on how moving support structure 30is loaded. Module 32 couples to and is supported by moving supportstructure 30. In one embodiment, module 32 couples to a major surface ofmoving support structure 30. A cover couples to module 32. The cover isremovable and is an interface to the distal end of femur 16.

As shown in FIG. 1 the distraction distance of distractor 10 is at aminimum height. In the example, the proximal end of tibia 18 has aprepared surface. The prepared surface can be a planar surface and canalso have a predetermined anterior-posterior (A-P) slope. In general,the word predetermined used herein above and below corresponds to a userselected value. The use of the word predetermined does not imply aspecific value or range. A minimum distraction distance of distractor 10occurs when surface 34 of fixed support structure 28 and a bottomsurface of moving support structure 30 couples to the prepared surfaceof the proximal end of tibia 18. The distraction distance is thedistance between the distal end of femur 16 and a proximal end of tibia18 under distraction. Note that the cover couples to the condyles offemur 16 and fixed support structure 28 couples to the prepared surfaceof the proximal end of tibia 18. The distance between the cover and thefixed support structure corresponds to the distraction distance. In oneembodiment, fixed support structure 28 comprises a frame 36. Frame 36has an opening for receiving moving support structure 30 therebyallowing the bottom surface of moving support structure 30 to couple tothe prepared bone surface of tibia 18.

FIG. 2 is an illustration of orthopedic measurement system 1 distractinga knee joint of a leg in accordance with an example embodiment. Asshown, the leg is in extension. Surface 34 of fixed support structure 28couples to prepared surface 40 of the proximal end of tibia 18. Knob 26couples to distraction mechanism 24. Rotating knob 26 increases ordecreases separation between moving support structure 30 and fixedsupport structure 28. In the example, knob 26 is rotated to increase thedistraction distance such that a bottom surface 42 of moving supportstructure 30 does not touch prepared bone surface 40. Module 32 andcover 38 are supported by moving support structure 30. Cover 38 couplesto the condyles of the distal end of femur 16. Thus, the distractiondistance includes the thickness of module 32 and cover 38 and ismeasured from the distal end of femur 16 to the prepared surface oftibia 18. In one embodiment, after distracting the joint the measurementdata can indicate that the prepared surface needs to be recut whencompared to the initial workflow. In the example, the workflow can bechanged under surgeon approval and the distractor removed to recut thetibia. Subsequent reinsertion of the distractor and distraction of thejoint would verify that the new workflow is now correct. The measurementdata related to the recut of the tibia and visualization of the workflowcould be displayed on the computer for viewing by the surgical team.

Distractor 10 includes a distance sensor on distractor 10 configured tomeasure the distraction distance. In one embodiment, the distance sensorcouples to distraction mechanism 24. Similarly, distractor 10 includesan angle sensor configured to measure the M-L tilt angle of movingsupport structure 30. In one embodiment, the angle sensor couples to theM-L tilt mechanism 22. Distractor 10 includes electronic circuitrycoupled to the distance sensor and the angle sensor. The electroniccircuitry of distractor 10 controls a measurement process and transmitsmeasurement data to computer 12. The measurement data can comprisedistraction distance data and M-L tilt data from the distance sensor andthe angle sensor. The distraction distance data and M-L tilt data can bedisplayed on display 14 in real-time. Alternatively, distractor 10 canhave a mechanical distance gauge and an M-L tilt gauge on distractor 10.

Module 32 also includes electronic circuitry and one or more sensors. Inone embodiment, module 32 includes a plurality of load sensorsconfigured to measure loading applied to the cover 38. The load sensorsare configured to measure load magnitudes at predetermined locations oncover 38. The electronic circuitry of module 32 is configured to controla load measurement process and transmit load data. Load data istransmitted from module 32 to computer 12. Computer 12 can process theload data from the plurality of load sensors (at predeterminedlocations) and calculate a load magnitude and a position of load where acondyle of femur 16 couples to cover 38. Computer 12 can providevisualization of the data to aid a surgeon in rapidly absorbing thequantitative measurement data. For example, a surface 48 of cover 38 orthe surface of module 32 can be shown on display 14 of computer 12.Contact points 44 and 46 can indicate where each condyle couples tocover 38. The contact points 44 and 46 can move in real-time if a changeoccurs that results in a parameter change that affects the contactpoints. For example, performing soft tissue tensioning which changesloading applied by a medial condyle or a lateral condyle of femur 16 todistractor 10 can result in movement of contact points 44 and 46. Theload magnitude at the point of contact can also be displayed. Thus, thesurgeon can receive the information as the surgical procedure is beingperformed with little or no time penalty but greatly increased knowledgeon the installation. It should be noted that module 32 is configured tobe removed from moving support structure 30. This allows module 32 to beused in another piece of equipment later in the surgery to take furthermeasurements, make adjustments, or verify that the final installationnumbers are similar to that generated when preparing bone surfaces forprosthetic component installation. Similarly, cover 38 can be removedfrom module 32. Cover 38 can be substituted for other covers designed tointerface with a different component. For example, cover 38 isconfigured to interface with the natural condyles of femur 16. Adifferent cover can be used to interface with a prosthetic femoralcomponent coupled to femur 16 later in the surgery to take furthermeasurements or verify the previous quantitative measurement data.

FIG. 3 illustrates cover 38, module 32, and distractor 10 in accordancewith an example embodiment. Moving support structure 30 is shownseparated from frame 36 of fixed support structure 28. Note that movingsupport structure 30 fits within an opening in frame 36 of fixed supportstructure 28 if the distraction distance is reduced by distractionmechanism 24. In one embodiment, moving support structure 30 has a majorsurface 50 configured to support module 32 when loaded by the kneejoint. A surface 58 of module 32 couples to major surface 50 of movingsupport structure 30. In the example, module 32 comprises a medial sideand a lateral side respectively configured to couple to a medial condyleand a lateral condyle of a knee joint. Major surface 50 of movingsupport structure 30 includes at least one alignment feature to retainand align module 32. For example, posts 52 extend from major surface 50of moving support structure 30. Posts 52 are received withincorresponding openings in module 32 when coupling a bottom surface 58 ofmodule 32 to major surface 50 of moving support structure 30. Movingsupport structure 30 can further comprise a wall 56 or walls that alignand retains module 32 to moving support structure 30. Posts 52 and wall56 prevent lateral forces from detaching module 32 from moving supportstructure 30 under knee joint loading. Module 32 can be removed bylifting module 32 vertically from surface 50 of moving support structure30. Module 32 is made to be removable so it can be placed in aprosthetic component such as an insert to make measurements later in thesurgical installation of the knee joint. Although, at least oneretaining feature is described for holding module 32 to major surface 50it is contemplated that other locking or retaining features can be used.The locking features can be on the sides, front, or back and cancomprise button locking that can be released to easily remove module 32from support structure 30.

Module 32 has electronic circuitry configured to control the measurementprocess and transmit the measurement data. The electronic circuitrycouples to one or more sensors for measuring parameters. In the example,a plurality of load sensors underlies the medial side and the lateralside of module 32. This supports measurement of the load magnitude andthe position of load due to the medial condyle and the lateral condyleof a femur coupled to cover 38. Module 32 is hermetically sealed andincludes a power source such as a battery, super capacitor, inductor, orother structure that can operate module 32 during a surgical procedure.In one embodiment, batteries 60 are used to power the electroniccircuitry in module 32. Module 32 further includes retaining structures54 and 70 extending from a periphery. Retaining structures 54 and 70 areconfigured to align and retain cover 38 to module 32. In the example,cover 38 slidably engages to module 32. In one embodiment, retainingfeature 70 fits into an opening of retaining feature 57 on cover 38 ascover 38 slides across module 32. Retaining feature 57 can flexed andincludes an opening. A force can be applied to cover 38 to flexretaining feature 57 of cover 38 over retaining feature 54 of module 32.Retaining feature 54 of module 32 couples through the opening inretaining feature 57 to retain cover 38 to module 32. Conversely, cover38 can be removed by flexing retaining feature 57 such that retainingfeature 54 of module 32 no longer extends through the opening inretaining feature 57. Cover 38 can then be lifted to separate cover 38from module 32. Cover 38 can then be moved to disengage retainingfeature 70 from the opening of the corresponding retaining feature ofcover 38 (that is not shown) thereby completely separating cover 38 frommodule 32.

A surface 62 and a surface 64 of module 32 is configured to couple tocorresponding interior surfaces of cover 38. The plurality of loadsensors underlie and couple to surface 62 and surface 64 of module 32.The plurality of load sensors are configured to couple to predeterminedlocations of a surface 66 and a surface 68 of cover 38. The plurality ofload sensors measures loading applied by condyles of the femur tosurfaces 66 and 68 of cover 38. The load data from the plurality of loadsensors is used to determine a load magnitude and position of load ofeach condyle to surfaces 62 and 64 in real-time thereby allowingadjustments in-situ.

FIG. 4 illustrates a cover 72 on module 32 configured having ananterior-posterior (A-P) slope of zero in accordance with an exampleembodiment. Cover 72 couples to module 32. Cover 72 is configured tocouple to the natural condyles of a femur. In one embodiment, cover 72is used prior to installation of the femoral prosthetic component and inconjunction with distractor 10 to support making one or more bone cutsto the distal end of a femur for receiving the femoral prostheticcomponent. Module 32 is configured to measure one or more parameters andtransmit measurement data to a computer for further processing. In theexample, disclosed above, module 32 measures loading applied by condylesof a femur on a medial and a lateral side of cover 72.

In one embodiment, a plurality of covers are provided with module 32.The covers can comprise a polymer or metal material. The covers can bemolded to lower cost of manufacture. In one embodiment, the plurality ofcovers provided with module 32 have different anterior-posterior (A-P)slopes. The covers having different A-P slopes are used to change thebiomechanics of the knee joint thereby affecting post-operative clinicaloutcome. Slope can be added to match the posterior tibial slope of theoriginal anatomical condition. Matching the A-P slope supports greaterknee flexion in the posterior cruciate ligament retaining total kneearthroplasty while a lesser slope can be used in a posterior-stabilizedtotal knee arthroplasty. The A-P slope affects the flexion gap, kneejoint stability, and posterior femoral rollback over the range ofmotion. Cover 72 has an anterior-posterior slope of zero degrees. Thus,cover 72 does not add A-P slope for assessment.

Alternatively, a mechanism could be added that can adjust theanterior-posterior slope of distractor 10 or surgical apparatusdisclosed herein. In one embodiment, the mechanism would tilt supportstructure 30. The mechanism could precisely control theanterior-posterior slope which could be measured using a tilt measuringsensor as disclosed herein and the tilt measurement data could be sentto the computer for display for the surgical team to review. The tiltmeasurement data could also be shown on a display coupled to distractor10.

FIG. 5 illustrates a cover 74 on the module configured having ananterior-posterior (A-P) slope of 2 degrees in accordance with anexample embodiment. Cover 74 couples to module 32. Cover 74 isconfigured to couple to the natural condyles of a femur. Thus, cover 74is used prior to installation of the femoral prosthetic component and inconjunction with distractor 10. Module 32 is configured to measure oneor more parameters and transmit measurement data to a computer forfurther processing. In the example, module 32 measures loading appliedby condyles of a femur on a medial and a lateral side of cover 74.

In general, a plurality of covers such as cover 74 and cover 72 of FIG.4 are provided with module 32. The covers having different A-P slopesare used to change the biomechanics of the knee joint thereby affectingpostoperative clinical outcome. Slope can be added to match theposterior tibial slope of the original anatomical condition. Matchingthe A-P slope supports greater knee flexion in the posterior cruciateligament retaining total knee arthroplasty while a lesser slope can beused in a posterior-stabilized total knee arthroplasty. The A-P slopeaffects the flexion gap, knee joint stability, and posterior femoralrollback over the range of motion. Cover 74 has an anterior-posteriorslope of +2 degrees for assessing the knee joint with added slope.

FIG. 6 illustrates a cover 76 on the module configured having ananterior-posterior (A-P) slope of 4 degrees in accordance with anexample embodiment. Cover 76 couples to module 32. Cover 76 isconfigured to couple to the natural condyles of a femur. Thus, cover 76is used prior to installation of the femoral prosthetic component and inconjunction with distractor 10. Module 32 is configured to measure oneor more parameters and transmit measurement data to a computer forfurther processing. In the example, module 32 measures loading appliedby condyles of a femur on a medial and a lateral side of cover 76.

In general, a plurality of covers such as cover 76, cover 74 of FIG. 5,and cover 72 of FIG. 4 are provided with module 32. The covers havingdifferent A-P slopes are used to change the biomechanics of the kneejoint thereby affecting postoperative clinical outcome. Slope can beadded to match the posterior tibial slope of the original anatomicalcondition. Matching the A-P slope supports greater knee flexion in theposterior cruciate ligament retaining total knee arthroplasty while alesser slope can be used in a posterior-stabilized total kneearthroplasty. The A-P slope affects the flexion gap, knee jointstability, and posterior femoral rollback over the range of motion.Cover 76 has an anterior-posterior slope of +4 degrees for assessing theknee joint with added slope. FIGS. 4, 5, and 6 are examples and thenumber of covers and A-P slopes can be more or less than shown.

FIG. 7 illustrates a cover 78 on module 32 configured to interface withnatural condyles of a femur in accordance with an example embodiment. Inone embodiment, distractor 10 is inserted in a knee joint with theproximal end of a tibia having a prepared bone surface and the distalend of a femur in a natural state. Natural condyles of the femur coupleto cover 78. Cover 78 will support leg movement over a range of motionwhen the knee joint is distracted. In the example, module 32 measuresloading applied by condyles of a femur on a medial and a lateral side ofcover 78. A plurality of covers identical to cover 78 can be providedeach having different A-P slopes to change the kinematics of the kneejoint. Also, the plurality of covers can comprise different sizes fordifferent knee sizes. For example, the covers can comprise small,medium, and large sizes that accommodate a large statistical sample ofthe population requiring knee joint replacement.

FIG. 8 illustrates a cover 73 on module 32 configured to interface witha femoral prosthetic component coupled to a femur in accordance with anexample embodiment. In one embodiment, distractor 10 is inserted in aknee joint with the proximal end of a tibia having a prepared bonesurface and the distal end of fitted with a femoral prostheticcomponent. Cover 73 is configured to interface with the condyles of thefemoral prosthetic component. In one embodiment, a surface of cover 73has a contour to support leg movement under load with the condyles ofthe femoral prosthetic component coupled to the surface. Cover 73supports all ligaments in place to stabilize the knee joint.

Cover 73 will support leg movement over a range of motion when the kneejoint is distracted. In the example, module 32 measures loading appliedon a medial side and a lateral side by the condyles of the femoralprosthetic component to cover 73. A plurality of covers identical tocover 73 can be provided each having different A-P slopes to change thekinematics of the knee joint. Also, the plurality of covers can comprisedifferent sizes for different knee sizes having different femoralprosthetic component sizes. For example, the covers can comprise small,medium, and large sizes that accommodate a large statistical sample ofthe population requiring knee joint replacement.

FIG. 9 illustrates a cover 77 on module 32 configured to interface witha femoral prosthetic component coupled to a femur in accordance with anexample embodiment. In one embodiment, distractor 10 is inserted in aknee joint with the proximal end of a tibia having a prepared bonesurface and the distal end fitted with a femoral prosthetic component.Cover 77 includes a support structure 79 that provides support when aligament is removed from the knee joint. In one embodiment, supportstructure 79 is coupled to covers disclosed herein above to form cover77. Alternatively, cover 77 can be provided having integral supportstructure 79. Cover 77 is configured to interface with the condyles ofthe femoral prosthetic component. A surface of cover 77 has a contour tosupport leg movement under load with the condyles of the femoralprosthetic component coupled to the surface.

Cover 77 will support leg movement over a range of motion when the kneejoint is distracted and a ligament removed. In the example, module 32measures loading applied on a medial side and a lateral side by thecondyles of the femoral prosthetic component to cover 77. A plurality ofcovers identical to cover 77 can be provided each having different A-Pslopes to change the kinematics of the knee joint. Support structure 79can couple to each of the plurality of covers. Also, the plurality ofcovers can comprise different sizes for different knee sizes havingdifferent femoral prosthetic component sizes. For example, the coverscan comprise small, medium, and large sizes that accommodate a largestatistical sample of the population requiring knee joint replacement.

FIG. 10A illustrates a frame 36 and a frame retaining support structure82 in accordance with an example embodiment. In one embodiment, fixedsupport structure 28 of FIG. 1 comprises retaining support structure 82and frame 36. Frame 36 is configured to be removable from frameretaining support structure 82. Frame retaining support structure 82allows for different frame sizes and different frame shapes to couple todistractor 10. Alternatively, frame 36 and frame retaining supportstructure 82 could be formed as a single structure. In one embodiment,frame retaining support structure 82 is formed as part of housing 20 ofFIG. 1. For example, a portion of housing 20 and frame retaining supportstructure 82 can be made as a single structure or formed in a moldthereby having a fixed geometric relationship between frame retainingsupport structure 82 and a distraction mechanism aligned and retained byhousing 20. Housing 20 can be formed from a polymer material, metal, ormetal alloy that supports loading applied by a knee joint whendistracted. Frame retaining support structure 82 includes retainingstructures 80 configured to retain and align frame 36 to frame retainingsupport structure 82. Frame 36 is coupled to frame retaining supportstructure 82 by pressing frame 36 into frame retaining support structure82 as indicated by arrow 86. Frame 36 includes retaining structures 84that interlock with retaining structures 80 of frame retaining supportstructure 82 such that frame 36 is rigid under loading of the knee jointand does not change a geometric relationship with frame retainingsupport structure 82 or housing 20 of FIG. 1. Conversely, frame 36 canbe removed by applying a force in an opposite direction as arrow 86 toframe 36 to release frame 36 from frame retaining support structure 82.A larger or smaller frame 36 can replace frame 36 that better fits thebone structure of the patient.

FIG. 10B illustrates the frame 36 coupled to frame retaining supportstructure 82 in accordance with an example embodiment. Retainingstructures 84 of frame 36 of FIG. 10A are shown interlocking withretaining structures 80 of frame retaining support structure 82. Frame36 is held in a predetermined position relative to frame retainingsupport structure 82 and the housing of the distractor. In oneembodiment, frame 36 and frame retaining support structure 82 are rigidand do not flex or torque under loading applied by the knee joint.Alternatively, support structure 82 can be designed to flex. The amountof flex could be quantified though a load or displacement curve based onthe forces applied to support structure 82. The displacement curve couldbe incorporated into the measurement data and processed by the computerto compensate for any flex incurred such that the measurement data iscorrect.

FIG. 11 illustrates different frame sizes in accordance with an exampleembodiment. Bone size varies across the population of patients requiringknee surgery. Different frame sizes are provided that support a majorityof the total knee arthroplasty surgeries performed each year. A frame 90is shown coupled to frame retaining support structure 82. A larger framecan be used if frame 90 is found to be too small for coupling to theprepared surface of a tibia. Frame 90 would then be removed from frameretaining support structure 82. A frame 92 can then be selected that islarger than frame 90 and installed onto frame retaining supportstructure 82. Thus, the distractor 10 of FIG. 1 supports removableframes and frames of different sizes to couple the distractor to theprepared surface of the tibia 18. The number of frame sizes provided canbe more or less than shown in FIG. 11.

FIG. 12A illustrates moving support structure 30 disengaged from M-Ltilt mechanism 22 in accordance with an example embodiment. M-L tiltmechanism 22 is shown coupling to a portion of distraction mechanism 24.Distraction mechanism 24 comprises a post 106 configured to raise orlower M-L tilt mechanism 22 and moving support structure 30 relative tothe fixed support structure 28 of FIG. 1. A key or handle can beinserted into coupler 104 of M-L tilt mechanism 22. The key when rotatedadjusts an M-L tilt angle of M-L tilt mechanism 22 when enabled. M-Ltilt mechanism 20 further includes a coupler 102 that is configured torotate as the key is rotated.

Moving support structure 30 includes a coupler 100 configured to coupleto coupler 102 of M-L tilt mechanism 22. Coupler 100 is inserted intocoupler 102 thereby retaining and aligning moving support structure 30to M-L distraction mechanism 22. M-L tilt mechanism 22 can be disengagedfrom coupler 102 thereby allowing coupler 102 and moving supportstructure 30 to freely rotate. In one embodiment, coupler 100 has asquare or rectangular shape that fits into a corresponding square orrectangular opening of coupler 102. Couplers 100 or 102 can beconfigured to have a temporary locking mechanism that retains movingsupport structure 30 to M-L tilt mechanism 22 while supportingremovability. Similar to fixed support structure 28, 90, and 92disclosed in FIGS. 10A, 10B, and 11 that are also removable, a pluralityof moving support structures can be provided of different sizes orstyles. In general, two or more moving support structures are providedwith distractor 10 of FIG. 1.

FIG. 12B illustrates moving support structure 30 coupled to M-L tiltmechanism 22 in accordance with an example embodiment. Moving supportstructure 30 as mentioned previously is removable from M-L tiltmechanism 22. This allows other moving support structures of differentsizes or styles to be used with distractor 10 shown FIG. 1. A modulehaving electronic circuitry and at least one sensor is placed on majorsurface 50 of moving support structure 30 to measure at least oneparameter. A cover configured to interface with natural condyles of afemur or a cover configured to interface with a femoral prostheticcomponent couples to the module. Distraction mechanism 24 is configuredto increase or decrease a distraction distance between moving supportstructure 30 and the fixed support structure 28 of FIG. 1. Distractionmechanism 24 raises or lowers both M-L tilt mechanism 22 and movingsupport structure 30. Moving support structure 30 is also configured totilt medially or laterally when M-L tilt mechanism 22 is adjusted. Ingeneral, moving support structure 30 can be removed from distractor 10.A plurality of moving support structures is provided to be used to fitdifferent anatomies with distractor 10. The moving support structurescan comprise different sizes and different styles. The different movingsupport structures can correspond to the different frames disclosed inFIG. 11. The moving support structures can accommodate the widediversity and variation of patient bone structure that is seen in anoperating room.

FIG. 13 is an illustration of M-L tilt mechanism 22 in accordance withan example embodiment. In the example, M-L tilt mechanism 22 is a wormgear drive 110. Worm gear drive 110 comprises two or more gears of whichat least one is a worm gear. As shown, worm gear drive 110 comprises aworm gear 112 and a gear 114. A housing 116 at least partially housesworm gear 112 and gear 114. Housing 116 retains, aligns, and supportsrotation of worm gear 112 to gear 114. Coupler 104 couples to worm gear112. In one embodiment, coupler 104 is a shaft of worm gear 112.Typically a key or handle couples to the opening in coupler 104 to allowa user to rotate worm gear 112.

Gear 114 couples to moving support structure 30. Housing 116 retains,aligns, and supports rotation of gear 114 when coupled to worm gear 112.As shown, M-L tilt mechanism 22 is decoupled from adjusting an M-L tiltangle of moving support structure 30. M-L tilt mechanism 22 is decoupledwhen the gear teeth of worm gear 112 are positioned such that the gearteeth of gear 114 do not couple to worm gear 112. Moving supportstructure 30 is free to tilt medially or laterally when M-L tiltmechanism 22 is decoupled and loaded by a knee joint. Gear 114 rotatesas moving support structure 30 rotates and vice versa. The module 32 andcover 38 disclosed in FIG. 2 couple between the condyles of the femurand moving support structure 30. The module 32 is supported by majorsurface 50 of moving support structure 30. Module 32 is aligned andretained to moving support structure 30 by posts 52 and sidewall 56. Themedial or lateral tilt of the knee joint corresponds to the balance ofthe knee joint and alignment of the leg.

In one embodiment, the teeth of worm gear 112 are coupled to the teethof gear 114 to engage M-L tilt mechanism 22 after moving supportstructure 30 has been allowed to freely move to an unequalized M-L tiltangle. The teeth of worm gear 112 are configured to couple to gear 114in a manner where they are self-locking. In other words, worm gear 112and gear 114 hold the position of the moving support structure 30 at theunequalized M-L tilt angle when engaged. The key or handle is insertedinto coupler 104 to rotate worm gear 112. In one embodiment, M-L tiltmechanism 22 is rotated an amount that equalizes the M-L tilt angle.This corresponds to a medial compartment being at an equal in height toa lateral compartment height. Worm gear drive 110 when rotated willchange the medial or lateral tilt depending on the direction of rotationand maintains self-locking at an adjusted medial or lateral tilt.Quantitative measurement data from a sensor is used to determine whenthe M-L tilt angle is equalized. Typically, the loading on the medialand lateral compartments will be unequal. Soft tissue tensioning can beused to adjust the loading applied by the condyles of the femur to thecover of the module. Equalizing the M-L tilt angle reduces an offset ofthe femur to the mechanical axis of the leg.

FIG. 14 is an illustration of distraction mechanism 24 in accordancewith an example embodiment. In one embodiment, distraction mechanism 24comprises a gear drive 132. Gear drive 132 can comprise two or moregears and is configured to increase or decrease separation between fixedsupport structure 28 and moving support structure 30 of distractor 10.Gear drive 132 comprises a post 120 and a gear 122. Post 120 extendsoutside housing 20 and is coupled to moving support structure 30.Housing 20 is configured to align, retain, and support movement of post120 and gear 122. Housing 20 positions gear 122 adjacent to post 120such that teeth of gear 122 engage with gear teeth 126 of post 120. Knob26 couples to gear 122 to facilitate rotation. In one embodiment,housing 20 supports movement of post 120 perpendicular to a plane offixed support structure 28.

Rotating knob 26 rotates gear 122 which in turn raises or lowers post120 depending on the direction of rotation. A spring 128 can be coupledto post 120 and housing 20. Spring 128 can provide a spring resistanceas post 120 is being raised from a minimum distraction distance. Asmentioned previously, the minimum distraction distance corresponds todistractor 10 having support structure 30 within the opening of fixedsupport structure 28. In one embodiment, the minimum distractiondistance occurs when both moving support structure 30 and fixed supportstructure 28 couples to a prepared surface of a tibia. In oneembodiment, a minimum height for a medial compartment and a lateralcompartment of a knee joint occurs when a bottom surface 34 of fixedsupport structure is co-planar with a bottom surface of moving supportstructure 30.

A distraction mechanism lock 124 is configured to prevent movement ofgear drive 132. Distraction lock mechanism 124 is coupled to housing 20and is configured to pivot. Distraction lock mechanism 124 is configuredto be enabled and disabled. A spring 130 supports pivoting ofdistraction lock mechanism 124 in a locked position whereby a tooth ofdistraction lock mechanism 124 is configured to engage with gear 122 toprevent movement. Spring 128 supports retention of the tooth ofdistraction lock mechanism 124 in gear 122 by applying a force on post120 that holds gear 122 against distraction lock mechanism 124 thatprevents a user from rotating knob 26. Moving support structure 30 willmaintain a distraction distance to fixed support structure 28 untildistraction lock mechanism 124 is released or disabled.

FIG. 15 is a block diagram of electronic circuitry 150 in distractor 10of FIG. 1 or module 32 of FIG. 1 in accordance with an exampleembodiment. Components of FIG. 1 may be referred to herein in thediscussion of electronic circuitry 150. Electronic circuitry 150 couplesto sensors 152 in distractor 10 or module 32. Electronic circuitry 150is configured to control a measurement process, receive measurement datafrom sensors 152 and transmit the measurement data to computer 12 ofFIG. 1 for further analysis and feedback. Parameters are measured bysensors 152 coupled to electronic circuitry 150 in module 32 ordistractor 10. Electronic circuitry 150 comprises a power managementcircuit 156, control logic 164, memory 158, and interface circuitry 160.A power source 154 couples to electronic circuitry 150 to power ameasurement process. Electronic circuitry 150 further includes atransceiver 162 and an antenna 174 that can be positioned on or within,or engaged with, or attached or affixed to or within, a wide range ofphysical systems including, but not limited to instruments, equipment,devices, prosthetic components, or other physical systems for use on orin human bodies and configured for sensing and communicating parametersof interest in real time.

In general, electronic circuitry 150 is configured to provide two-waycommunication between distractor 10 or module 32 and computer 12. In oneembodiment, distractor 10 provides quantitative measurement data relatedto a distraction distance, medial-lateral tilt, or anterior-posteriortilt of distractor 10. In one embodiment, module 32 providesquantitative measurement data related to load magnitude, position ofload, position, tilt, balance, and alignment. Alternatively, distractor10 can have mechanical gauges to provide measurement data local to thedevice. The measurement data from distractor 10 or module 32 can be usedby computer 12 in a kinematic assessment to support installation ofprosthetic components to ensure optimal loading, balance, and alignmentthat improves performance and reliability based on clinical evidence.

Power source 154 provides power to electronic circuitry 150 and sensors152. The power source 154 can be temporary or permanent. In oneembodiment, the power source can be rechargeable. Charging of the powersource 154 can comprise wired energy transfer or short-distance wirelessenergy transfer. A charging power source to recharge power source 154can include, but is not limited to, a battery or batteries, analternating current power supply, a radio frequency receiver, anelectromagnetic induction coil, a photoelectric cell or cells, athermocouple or thermocouples, or a transducer energy transfer. Powersource 154 has sufficient energy to operate electronic circuitry 150 indistractor 10 or module 32 for one or more surgeries with a singlecharge. Distractor 10 or module 32 can utilize power managementtechnologies to minimize the power drain of power source 154 while inuse and when it is idling. In one embodiment, distractor 10, module 32,or both can be a disposable device after a surgery is completed.

In one embodiment, power source 154 in distractor 10 or module 32 is arechargeable battery. The rechargeable battery can be recharged by themethods disclosed herein above. Alternatively, power source 154 can be asuper capacitor, an inductor, or other energy storage device. Anexternal charging source can be coupled wirelessly to the rechargeablebattery, capacitor, or inductive energy storage device through anelectromagnetic induction coil by way of inductive charging. Thecharging operation can be controlled by power management circuit 156within electronic circuitry 150. In one embodiment, power managementcircuit 156 supports operation of distractor 10 or module 32 duringcharging thereby allowing the surgery to continue if a low charge onpower source 154 is detected. For example, power can be transferred tothe battery, capacitive energy storage device, or inductive energystorage device by way of efficient step-up and step-down voltageconversion circuitry. This conserves operating power of circuit blocksat a minimum voltage level to support the required level of performance.

Power management circuit 156 is configured to operate under severe powerconstraints. In one embodiment, power management circuit 156 controlspower up, power down, and minimizes power usage. The power managementcircuit 156 can also reduce power during operation of the system. Thepower management circuit 156 can turn off or reduce the power deliveredto circuits that are not being used in a specific operation. Similarly,if the system is idle and not being used, the power management circuit156 can put other unused circuitry in a sleep mode that awakens prior tothe next measurement being made. Power management circuit 156 caninclude one or more voltage regulation circuits that provide a pluralityof different stable voltages to electronic circuitry 150 and sensors 152to minimize power dissipation.

In one configuration, a charging operation of power source 154 canfurther serve to communicate downlink data to electronic circuitry. Forinstance, downlink control data can be modulated onto the energy sourcesignal and thereafter demodulated from an inductor in electroniccircuitry 150. This can serve as a more efficient way for receivingdownlink data instead of configuring an internal transceiver withinelectronic circuitry 150 for both uplink and downlink operation. As oneexample, downlink data can include updated control parameters thatdistractor 10 or module 32 uses when making a measurement, such asexternal positional information or for recalibration purposes. It canalso be used to download a serial number or other identification data.

Control logic 164 controls a measurement process or sequence thatengages the sensors, converts the measurement data into a useableformat, and transmits the information. Control logic 164 can comprisedigital circuitry, a microcontroller, a microprocessor, an ASIC(Application Specific Integrated Circuit), a DSP (Digital SignalProcessing), a gate array implementation, a standard cellimplementation, and other circuitry. Control logic 164 couples to memory158. Memory 158 is configured to store measurement data, softwareroutines, diagnostics/test routines, calibration data, calibrationalgorithms, workflows, and other information or programs. In oneembodiment, one or more sensors may be continuously enabled and controllogic 164 can be configured to receive the measurement data, store themeasurement data in memory, or transmit the measurement data inreal-time. Prior to sealing the device and sterilizing the device forpackaging, sensors coupled to electronic circuitry 150 can becalibrated. Typically, the sensors are exercised against a referencethat can include varying conditions such as environmental changes.Differences between a sensor and the reference can be stored in memory158. The calibration data can then be used in conjunction with themeasurements taken by the sensor to correct the sensor output.Alternatively, the calibration data can be provided from the device to acomputer used to display the measurement data in the surgicalenvironment. The computer then uses the calibration data to correct themeasurement data from the sensor before displaying it to the surgicalteam. Control logic 164 can include dedicated ports that couple to asensor to continuously receive measurement data or receive at highsample rates measurement data. Alternatively, control logic 164 canselect a sensor to be measured. For example, multiple sensors can becoupled to control logic 164 via a multiplexer. Control logic 164controls which sensor is coupled through the multiplexer to receivemeasurement data. Multiplexed measurement data works well when themeasurement data is not critical or can be sampled occasionally asneeded. Control logic 164 can also select and receive measurement datafrom different sensors in a sequence. Control logic 164 can beconfigured to monitor the measurement data from a sensor but transmitmeasurement data only when a change occurs in the measurement data.Furthermore, control logic 164 can modify the measurement data prior totransmitting the measurement data to computer 12. For example, themeasurement data can be corrected for non-linearity using calibrationdata.

Interface circuitry 160 couples between sensors 152 and control logic164. Interface circuitry 160 supports conversion of a sensor output to aform that can be received by computer 12. Interface circuitry 160comprises digital circuitry and analog circuitry. The analog circuitrycan include multiplexers, amplifiers, buffers, comparators, filters,passive components, analog to digital converters, and digital to analogconverters to name but a few. In one embodiment interface circuitry 160uses one or more multiplexers to select a sensor for providingmeasurement data to control logic 164. Control logic 164 is configuredto provide control signals that enable the multiplexer to select thesensor for measurement. The multiplexer can be enabled to deliver themeasurement data to control logic 164, memory 158, or to be transmittedin real-time. Typically, at least one analog to digital conversion ordigital to analog conversion of the measurement data occurs via theinterface circuitry 160.

Sensors 152 couple through interface circuitry 160 to control logic 164.Alternatively, interface circuitry 160 can couple directly to circuitryfor transmitting measurement data as it is measured. The physicalparameter or parameters of interest measured by sensors 152 can include,but are not limited to, height, length, width, tilt/slope, position,orientation, load magnitude, force, pressure, contact point location,displacement, density, viscosity, pH, light, color, sound, optical,vascular flow, visual recognition, humidity, alignment, rotation,inertial sensing, turbidity, bone density, fluid viscosity, strain,angular deformity, vibration, torque, elasticity, motion, andtemperature. Often, a measured parameter is used in conjunction withanother measured parameter to make a kinetic and qualitative assessment.In joint reconstruction, portions of the muscular-skeletal system can beprepared to receive prosthetic components. Preparation includes bonecuts or bone shaping to mate with one or more prosthesis. Parameters canbe evaluated relative to orientation, alignment, direction,displacement, or position as well as movement, rotation, or accelerationalong an axis or combination of axes by wireless sensing modules ordevices positioned on or within a body, in an instrument, an appliance,a tool, equipment, prosthesis, or other physical system.

The sensors can directly or indirectly measure a parameter of interest.For example, a load sensor in module 32 of FIG. 1 can comprise acapacitor that has an elastic dielectric that can compress when a loadis applied to the capacitor. This is an indirect form of sensing aparameter (load) where the capacitance of the capacitor varies withloading. The capacitive measurement data is sent to computer 12 of FIG.1 for further processing. Computer 12 can include software andcalibration data related to the elastic capacitors. The load measurementdata can be converted from capacitance values to load measurements. Thecalibration data can be used to curve fit and compensate for non-linearoutput of a sensor over a range of operation. Furthermore, theindividual sensor measurement can be combined to produce othermeasurement data by computer 12. In keeping with the example of loadmeasurement data, the individual load measurement data can be combinedor assessed to determine a location where the load is applied to asurface to which the load sensors couple. The measurement data can bedisplayed on a display that supports a surgeon rapidly assimilating themeasurement data. For example, the calculated measurement data on thelocation of applied load to a surface may have little or no meaning to asurgeon. Conversely, an image of the surface being loaded with a contactpoint displayed on the surface can be rapidly assimilated by the surgeonto determine if there is an issue with the contact point.

In one embodiment, the orthopedic measurement system transmits andreceives information wirelessly. Wireless operation reduces clutterwithin the surgical area, wired distortion, wired disconnect, orlimitations on, measurements caused by the potential for physicalinterference by, or limitations imposed by, cables connecting a devicewith an internal power with data collection, storage, or displayequipment in an operating room environment. Electronic circuitry 150includes wireless communication circuitry 162. In one embodiment,wireless communication circuitry 162 is low power and configured forshort range telemetry. Typically, distractor 10, module 32, and computer12 are located in an operating room such that the transmission ofmeasurement data from distractor 10 or module 32 to computer 12 is lessthan 10 meters. As illustrated, the exemplary communications systemcomprises wireless communication circuitry 162 of distractor 10 ormodule 32 and receiving system wireless communication circuitry 180 ofcomputer 12. The distractor 10 or module 32 wireless communicationscircuitry are inter-operatively coupled to include, but not limited to,the antenna 174, a matching network 172, the telemetry transceiver 170,a CRC circuit 168, a data packetizer 166, and a data input 176. Wirelesscommunication circuitry 162 can include more or less than the number ofcomponents shown and are not limited to those shown or the order of thecomponents.

Similarly, computer 12 includes wireless communication circuitry 180that comprises an antenna 182, a matching network 184, a telemetryreceiver 186, a CRC circuit 188, and a data packetizer 190. Notably,other interface systems can be directly coupled to the data packetizer190 for processing and rendering sensor data. In general, electroniccircuitry 150 couples to sensors 152 and is configured to transmitquantitative measurement data to computer 12 in real-time to process,display, analyze, and provide feedback. In one embodiment, distractor 10includes a magnetic linear sensor configured to measure a distance ofdistraction and a magnetic angle sensor to measure tilt, slope, orangle. Electronic circuitry 150 is coupled to the magnetic linear sensorand the magnetic angle sensor in distractor 10. The distraction distancedata and the M-L tilt measurement data is transmitted by electroniccircuitry 150 in distractor 10 to computer 12 and is displayed ondisplay 14. In one embodiment, module 32 includes a plurality of loadsensor configured to measure load magnitude at predetermined locationsof cover 38 of FIG. 14. Electronic circuitry 150 in module 32 couples tothe plurality of load sensors. Module 32 can further include inertialsensors and other parameter measurement sensors. The measurement datafrom the plurality of load sensors and the inertial sensors istransmitted to computer 12. Computer 12 can further calculate a point ofcontact to the surface of the cover 38 on a medial side and a lateralside. Computer 12 can calculate the load magnitude at the point ofcontact on the medial side or the lateral side. The module can furtheruse the inertial sensors as a position measurement system or a trackingsystem. The tracking data is also sent to computer 12. The results canalso be displayed on display 14 of computer 12. Redundant measurementdata can be generated from distractor 10 and module 32 such as M-L tiltor A-P tilt. The redundant measurement data can be compared to ensureaccuracy of the measurement.

In general, electronic circuitry 150 is operatively coupled to one ormore sensors 152 to control a measurement process and to transmitmeasurement data. Electronic circuitry 150 can be placed near sensors152 or housed with the sensors to simplify coupling to the sensors. Asmentioned previously, electronic circuitry 150 can be placed indistractor 10 and electronic circuitry 150 can be placed in module 32 tocontrol a measurement process and transmit measurement data in eachdevice. Electronic circuitry 150 couples to the magnetic angle sensorand the magnetic distance sensor in distractor 10. Electronic circuitry150 controls a measurement process of the magnetic angle sensor and themagnetic distances sensor of distractor 10 and transmits measurementdata to computer 12. Similarly, electronic circuitry 150 couples tosensors of module 32. Electronic circuitry 150 controls a measurementprocess of the sensors of module 32 and transmits measurement data tocomputer 12. In one embodiment, the process of transmitting data fromdistractor 10 is independent from module 32. Alternatively, theelectronic circuitry 150 of distractor 10 can be in communication withthe electronic circuitry 150 of module 32 to control the measurementprocesses and transmission of measurement data. In one embodiment, thetransmission of the measurement data from different components can besent on different channels or the measurement data can be sent atdifferent times on the same channel.

As mentioned previously, wireless communication circuitry comprises datainput 176, data packetizer 166, CRC circuit 168 telemetry transmitter170, matching network 172, and antenna 174. In general, measurement datafrom sensors 152 is provided to data input 176 of wireless communicationcircuitry 162. The measurement data can be provided from interfacecircuitry 160, from the control logic 164, from memory 158, or fromcontrol logic 164 thru interface circuitry 160 to data input 176. Themeasurement data can be stored in memory 158 prior to being provided todata input 176. The data packetizer 166 assembles the sensor data intopackets; this includes sensor information received or processed bycontrol logic 164. Control logic 164 can comprise specific modules forefficiently performing core signal processing functions of thedistractor 10 or module 32. Control logic 164 provides the furtherbenefit of reducing the form factor to meet dimensional requirements forintegration into distractor 10 or module 32.

The output of data packetizer 166 couples to the input of CRC circuit168. CRC circuit 168 applies error code detection on the packet data.The cyclic redundancy check is based on an algorithm that computes achecksum for a data stream or packet of any length. These checksums canbe used to detect interference or accidental alteration of data duringtransmission. Cyclic redundancy checks are especially good at detectingerrors caused by electrical noise and therefore enable robust protectionagainst improper processing of corrupted data in environments havinghigh levels of electromagnetic activity. The output of CRC circuit 168couples to the input of telemetry transceiver 170. The telemetrytransceiver 170 then transmits the CRC encoded data packet through thematching network 172 by way of the antenna 174. Telemetry transceiver170 can increase a carrier frequency in one or more steps and add theinformation or measurement data from distractor 10 or module 32 to thecarrier frequency. The matching network 172 provides an impedance matchfor achieving optimal communication power efficiency between telemetrytransmitter 170 and antenna 174.

The antenna 174 can be integrated with components of the distractor 10or module 32 to provide the radio frequency transmission. The substratefor the antenna 174 and electrical connections with the electroniccircuitry 150 can further include the matching network. In oneembodiment, the antenna and a portion of the matching network 172 can beformed in the printed circuit board that interconnects the componentthat comprise electronic circuitry 150. This level of integration of theantenna and electronics enables reductions in the size and cost ofwireless equipment. Potential applications may include, but are notlimited to any type musculoskeletal equipment or prosthetic componentswhere a compact antenna can be used. This includes disposable modules ordevices as well as reusable modules or devices and modules or devicesfor long-term use.

The process for receiving wireless communication circuitry 180 is theopposite of the sending process. Antenna 182 receives transmittedmeasurement data from wireless communication circuitry 162. Wirelesscommunication circuitry 162 can transmit at low power such thatreceiving wireless communication circuitry 180 must be in proximity, forexample within an operating room to receive measurement data. Antenna182 couples to matching network 184 that efficiently couples themeasurement data to telemetry transmitter circuit 186. The measurementdata can be sent on a carrier signal that supports wirelesstransmission. The measurement data is stripped off from the carriersignal by telemetry transmitter 186. The measurement data is received byCRC circuit 188 from telemetry transmitter 186. CRC circuit 188 performsa cyclic redundancy check algorithm to verify that the measurement datahas not been corrupted during transmission. The CRC circuit 188 providesthe checked measurement data to data packetizer 190. Data packetizer 190reassembles the measurement data where it is provided to usb interface192. USB interface 192 provides the measurement data to computer 12 forfurther processing. It should be noted that the measuring, transmitting,receiving, and processing of the measurement data can be performed inreal-time for use by a surgeon installing the knee joint.

FIG. 16 is an illustration of a magnetic angle sensor 206 coupled to M-Ltilt mechanism 22 in accordance with an example embodiment. Theillustration includes a magnified view of distractor 10 corresponding toM-L tilt mechanism 22. M-L tilt mechanism 22 couples to moving supportstructure 30 and can adjust the M-L tilt angle of moving supportstructure 30. M-L tilt mechanism 22 can be disengaged from movingsupport structure 30 thereby allowing moving support structure 30 tofreely move medially or laterally. A neutral or 0 degrees medial-lateraltilt occurs when a plane of moving support structure 30 is parallel to aplane of fixed support structure 28. Referring briefly to FIG. 12A acoupler 100 of moving support structure 30 is inserted into a coupler102 of M-L tilt mechanism 22 to retain and align moving supportstructure 30 to M-L tilt mechanism 22. Coupler 102 freely rotates withM-L tilt mechanism 22 when worm gear 112 of FIG. 13 is disengaged.Conversely, the movement of coupler 102 and moving support structure 30are locked into the movement of M-L tilt mechanism 22 when worm gear 112is engaged with gear 114. In other words, M-L tilt mechanism 22 whenengaged can forcibly adjust the M-L tilt angle thereby rotating movingsupport structure 30 and coupler 102 of FIG. 12A medially or laterally.

In one embodiment, magnetic angle sensor 206 comprises a Hall EffectSensor 204 and a magnet 200. The Hall Effect Sensor 204 can be anintegrated circuit that is placed in proximity to magnet 200. Ingeneral, the Hall Effect Sensor 204 comprises an array of sensors thatdetects the perpendicular component of a magnetic field generated bymagnet 200. Each sensor generates a signal and the signals are summedand amplified. In one embodiment, the array of sensors are aligned in acircle. Thus, any rotation of the magnet 200 is detected and the amountof rotation can be calculated. In the example, magnet 200 is coupled tocoupler 102 thereby rotating as coupler 102 rotates. Hall Effect Sensor204 is placed adjacent to magnet 200 and within the magnetic fieldgenerated by magnet 200. Magnetic angle sensor 206 is a sensor thatcouples to electronic circuitry 150 as disclosed in FIG. 15 to storeangle sensor data or transmit angle sensor data in real-time. Arrow 202indicates rotation of magnetic 200 in a clockwise direction when facingdistractor 10. For example, the clockwise direction can correspond to amedial tilt. Magnetic angle sensor 206 can be calibrated to measure zerodegrees when the plane of fixed support structure 28 is parallel withthe plane of moving support structure 30. Hall Effect Sensor 204measures the rotation of magnetic 200 and is calibrated to measure thedegrees of rotation as moving support structure 30 tilts medially. Theangle sensor data is sent to the computer 12 of FIG. 1 and the amount ofmedial tilt is displayed on display 14 of FIG. 1 in real-time. Othersensor types are also contemplated for measuring tilt or angle. Forexample, an inclinometer, an accelerometer, a gyroscope, a mechanicalsensor, GPS, an altimeter, a level gauge, an optical sensor, an acousticsensor, video sensing, a pitch and roll indicator are but a few of thesensors that can be adapted to measuring tilt and generatingquantitative measurement data that can be sent to a computer for use bya surgical team.

FIG. 17 is an illustration magnetic angle sensor 206 in distractor 10 inaccordance with an example embodiment. Magnetic angle sensor 206comprises Hall Effect Sensor 204 and magnet 200. In one embodiment,magnet 200 is coupled to and centered on coupler 102 such that magnet200 rotates with coupler 102. Hall Effect Sensor 204 can be mounted on aprinted circuit board 208 that couples to electronic circuitry 150 ofFIG. 15 that can be located in a different area of distractor 10. Aplanar surface of magnet 200 is positioned centrally to a planar surfaceof Hall Effect Sensor 204. As mentioned previously, the Hall EffectSensor 204 is placed within the magnetic field generated by magnet 200.

FIG. 18 is an illustration of moving support structure 30 tiltinglaterally in accordance with an example embodiment. In the example,magnet 200 is coupled to coupler 102 thereby rotating as coupler 102rotates. Hall Effect Sensor 204 is placed adjacent to magnet 200 andwithin the magnetic field generated by magnet 200. The magnetic anglesensor 206 couples to electronic circuitry 150 as disclosed in FIG. 15to receive and transmit magnetic angle sensor data. Arrow 210 indicatesrotation of magnetic 200 in a counter-clockwise direction when facingdistractor 10. For example, the counter-clockwise direction cancorrespond to a lateral tilt. Magnetic angle sensor 206 can becalibrated to measure zero degrees when the plane of fixed supportstructure 28 is parallel with the plane of moving support structure 30.Hall Effect Sensor 204 measures the rotation of magnetic 200 and iscalibrated to measure the degrees of rotation as moving supportstructure 30 tilts laterally as shown. The magnetic angle sensor data issent to the computer 12 of FIG. 1 and the amount of medial tilt isdisplayed on display 14 of FIG. 1 in real-time.

FIG. 19 is an illustration of a magnetic distance sensor 224 indistractor 10 in accordance with an example embodiment. In oneembodiment magnetic distance sensor 224 comprises a magnet 220 and aLinear Hall Sensor 222. The magnetic distance sensor 224 providescontactless position measurement. Magnet 220 is a two pole magnet.Linear Hall Sensor 222 can measure absolute position of lateral movementwhen placed in the magnetic field of magnet 220. The strength of themagnetic field measured by Linear Hall Sensor 222 corresponds todistance but is not linear to distance. Linear Hall Sensor 222 relatesthe non-linear change in magnetic field strength per unit distance andlinearizes the output. Linear Hall Sensor 222 couples to electroniccircuitry 150 of FIG. 15 in distractor 10 where electronic circuit 150is configured to control a measurement process and transmit distractiondistance data. Other sensor types are also contemplated for measuringdistance. For example, an optical sensors, an ultrasonic sensors, GPS,mechanical gauges, lasers, displacement sensors, video sensing, contactsensors, eddy current sensors are but a few of the sensors that can beadapted to measuring distance and generating quantitative measurementdata that can be sent to a computer for use by a surgical team.

In one embodiment, Linear Hall Sensor 222 is coupled to a portion ofdistraction mechanism 24 that moves relative to housing 20 and fixedsupport structure 28 of FIG. 14. For example, Linear Hall Sensor 222 cancouple to post 120 of distraction mechanism 24 that increases ordecreases a distraction distance of moving support structure 30 relativeto fixed support structure 28. Operation of distraction mechanism 24 andpost 120 is disclosed in more detail in FIG. 14. Magnet 220 is coupledto housing 20 such that Linear Hall Sensor 222 is in proximity to magnet220. In one embodiment, Linear Hall Sensor 222 and magnet 220 align toan axis to which a distance is measured. In the example, the axis canalign with pole 120. A reference distance can be establishedcorresponding to distractor 10 being at a minimum distraction distancefor the medial and lateral compartment heights with a medial-lateraltilt angle of zero. The reference distance can be displayed on display14 of computer 12 of FIG. 1. As post 120 changes position to increase adistraction distance of distractor 10, Linear Hall Sensor 222 measuresthe magnetic field from magnet 220 whereby the measured magnetic fieldstrength corresponds to distance of Linear Hall Sensor 222 from magnet220. The measured change in height can be added to the referencedistance to arrive at the medial and lateral compartment heights.Electronic circuitry 150 in distractor 10 receives and transmitsdistraction distance data from Linear Hall Sensor 222 to computer 12 ofFIG. 1. Alternatively, Linear Hall Sensor 222 can be placed on housing20 and magnet 220 can be coupled to post 120 such that magnet 220 movesrelative to Linear Hall Sensor 222. In one embodiment, Magnetic distancesensor 224 can be used in conjunction with magnetic angle sensor 206 tocalculate medial or lateral compartment heights. Computer 12 can receivethe height measurement data and the angle measurement data geometricallycalculate the medial height and the lateral compartments heights. In oneembodiment, the medial height and the lateral compartment heights willbe measured at a known position on the medial surface of the module 32and a known position on the lateral surface of module 32.

FIG. 20 is an illustration of display 14 of computer 12 as shown in FIG.1 in accordance with an example embodiment. Electronic circuitry 150 ofFIG. 15 in distractor 10 transmits distraction distance data and M-Ltilt data to computer 12. In a surgical environment reducing patienttime under anesthesia lowers patient risk of complication or death. Asurgeon using quantitative measurement data during orthopedic surgerymust absorb the measurement data rapidly to support installation ofprosthetic components in the shortest possible time. Display 14 of FIG.1 can visualize data in a manner that allows the surgeon to rapidlydetermine if the measurement data verifies the subjective feel of aninstallation or if the installation needs correction and how much.Moreover, display 14 of FIG. 1 supports real-time measurement as acorrection or adjustment is made.

In one embodiment, M-L tilt data is displayed on a meter 230. Meter 230can comprise a first indicator 232 and a second indicator 234.Indicators 232 and 234 comprises opposing pointers that point to agraduated scale on either side of meter 230 corresponding to degrees ofmedial or lateral tilt. This supports at a glance an imbalance or offsetof alignment. Meter 230 can also be used during an equalization step.The equalization step engages M-L tilt mechanism 22 of FIG. 1 toforcibly adjust the M-L tilt to zero. The M-L tilt at zero degreescorresponds to a plane of fixed support structure 28 of FIG. 1 beingparallel to a plane of moving support structure 30 of FIG. 1. The actualquantitative measurement data related to M-L tilt can be displayed withboxes 236, 238, and 240 on display 14.

In one embodiment, distraction distance data is displayed on display 14.Distraction distance corresponds to a distance between a distal end of afemur and a proximal end of a tibia and is displayed visually on display14. A bar chart 250 provides a visual representation of the distractiondistance. Distraction distance values are displayed on one side of thebar graph. A bar in bar chart 250 indicates the distance and is adjacentto the distance values. The distraction distance value can also bedisplay in a box 252 on display 14. A medial or lateral heightrespectively of the medial compartment and the lateral compartment of aknee joint can be calculated by computer 12 and displayed by display 14.

FIG. 21 is an illustration of a top view of module 32 in accordance withan example embodiment. Module 32 includes at least one sensor formeasuring a parameter of the musculoskeletal system. In the example,module 32 includes a plurality of load sensors configured to measure aload applied to a surface 62 and a surface 64 also shown in FIG. 3. Theplurality of load sensors are coupled to predetermined locations ofsurface 62 and 64 that define an area of contact. In one embodiment,each load sensor couples to a vertex of a polygon. As previouslymentioned, cover 38 as shown in FIG. 2 couples to module 32 when placedin distractor 10. Cover 38 couples to surface 62 and 64. Thepredetermined locations of the plurality of load sensors translates tolocations on cover 38 that determine a location of medial or lateralcondyle contact on cover 38.

Module 32 can also be used in trialing the knee joint prior to a finalinstallation of final prosthetic components. For example, a tibialprosthetic component and femoral prosthetic component are installedusing the quantitative measurement data from distractor 10 and module 32as shown in FIG. 1 to determine bone cuts, alignment, and balance. Atrialing insert can then be inserted in the tibial prosthetic to takefurther measurements. The trialing insert can comprise module 32 and acover. The cover is configured to couple to the femoral prostheticcomponent. The combined thickness of module 32 and the cover isdetermined by the bone cuts and measurements made by distractor 10. Inone embodiment, the insert comprising module 32 and the cover isinserted in the tibial prosthetic component. Measurements from module 32as a trialing insert should be similar to the measurements taken withdistractor 10 and module 32. Further adjustments can be made to finetune the prosthetic component installation using quantitativemeasurement data. The trialing insert can then be removed and the finalinsert installed in the knee joint. The final insert should haveloading, position of load, balance, and alignment approximately equal tothat measured using the trialing insert.

FIG. 22 is an illustration of module 32 with a portion of an enclosureremoved in accordance with an example embodiment. Module 32 compriseselectronic circuitry 150 and at least one sensor configured to measure aparameter. Module 32 comprises a first support structure and a secondsupport structure configured to form a housing that is hermeticallysealed. In the example embodiment, a plurality of load sensors 272 areshown on a medial side of module 32 to measure loading applied to themedial side of module 32. Plurality of load sensors 272 are placed atpredetermined locations in module 32 to support measuring a position ofload applied to the medial side. A load plate that is not shown wouldoverlie plurality of load sensors 272. A plurality of load sensors arealso placed at predetermined locations on a lateral side of module 32although they cannot be seen in FIG. 22. A load plate 274 overlies theplurality of load sensors on the lateral side. Load plate 274distributes loading to a load sensor. In one embodiment, the pluralityof load sensors 272 are formed in flexible interconnect 276. Similarly,the plurality of load sensors underlying load plate 274 can be formed ininterconnect 280. The leads of the plurality of load sensors 272 coupleto electronic circuitry 150 as previously disclosed in FIG. 15.

Electronic circuitry 150 can be coupled to a printed circuit board 282.Electronic components can be coupled to, formed in, or interconnected toform a circuit on printed circuit board 282. In one embodiment, leadsfrom plurality of load sensors 272 on flexible interconnect 276 and 280can be coupled to printed circuit board 282 by solder bumping.Electronic circuitry 150 is placed in a region of module 32 that is notsubject to loading by the musculoskeletal system. Electronic circuitry150 controls a measurement process and transmits measurement data fromplurality of load sensors 272. Electronic circuitry 150 receives powerfrom a power source. In one embodiment, the power source comprisesbatteries 270. At least a portion of each battery underlies a portion ofa surface that is loaded by the musculoskeletal system. The battery formfactor is such that compression of module 32 under load by themusculoskeletal system does not touch batteries 270. Batteries 270 arecoupled to electronic circuitry 150 by flexible interconnect 278 and284. Flexible interconnect 278 and 284 can couple to electroniccircuitry 150 by solder bump to printed circuit board 282.

FIG. 23 is an exploded view of an insert 308 prosthetic component inaccordance with an example embodiment. Insert 308 comprises a cover 300and module 32. Distractor 10 of FIG. 1 uses module 32 to support one ormore bone cuts for installation of one or more prosthetic components ofthe knee joint. In general, the load magnitude, position of load,balance, and alignment of the knee joint is measured. The size andheight of the prosthetic components are taken into account in the bonecuts supported by distractor 10. After a tibial bone cut has beencompleted a tibial prosthetic component can be installed in a proximalend of a tibia. The tibial prosthetic component can be a trial tibialprosthetic component or a final tibial prosthetic component. Similarly,a femoral prosthetic component can be installed on a distal end of afemur after the femoral bone cuts on a distal end of the femur are made.

Module 32 comprises a support structure 302 and a support structure 304.Support structures 302 and 304 when coupled together form a housing forat least one sensor, a power source, and electronic circuitry 150. Thehousing is hermetically sealed by welding, adhesive, glue, mechanicalcoupling, blocking channels or other techniques. Support structure 302has a surface 62 and a surface 64 configured to respectively couple toan articular surface 310 and an articular surface 312 of cover 300.Articular surfaces 310 and 312 support movement of the knee joint over arange of motion of the leg. Support structure 304 has a surface 318 thatcouples to a surface of the tibial prosthetic component.

Electronic circuitry 150 is placed in a lightly loaded or unloaded areaof module 32. Electronic circuitry 150 controls a measurement processand transmits measurement data to a computer 12 shown in FIG. 1. Thecomputer 12 is in the operating room and the transmission of themeasurement data is short range. In one embodiment, a first plurality ofload sensors underlie and couple to surface 64 at predeterminedlocations. Similarly, a second plurality of load sensors underlie andcouple to surface 62 at predetermined locations. The predeterminedlocations correspond to vertexes of a polygon that define a measurementregion. Load plates 274 couple between surface 64 and surface 62 ofsupport structure 302 and the first or second plurality of load sensors.Load plates 274 distribute loading applied to surface 260 or surface 262to the first or second plurality of load sensors. A power source couplesto electronic circuitry 150 and the first and second plurality of loadsensors. In one embodiment, the power source comprises batteries 270.Batteries 270 can be single use or rechargeable batteries.

Cover 300 couples to module 32. Module 32 and cover 300 have one or moreretaining features that couple module 32 to cover 300. The retainingfeatures allow cover 300 to be removed from module 32. Cover 300 furtherincludes openings 306 that are configured to receive a handle to directand install insert 308 in the knee joint. In one embodiment, a pluralityof covers can be provided. The plurality of covers each have a differentheight or thickness. The combined thickness of module 32 and a covercorresponds to a height or thickness of a final insert that is installedinto the prosthetic knee joint. The plurality of covers can also includecovers of a different size that support optimal fitting for differentbone sizes. In general, a cover is selected that corresponds to apatient femur and tibia bone size and a thickness corresponding to aspacing between the femoral prosthetic component and the tibialprosthetic component.

Insert 308 is installed in the knee joint. Insert 308 couples to and isretained by the trial or permanent tibial prosthetic component. Cover300 and module 32 have a height or thickness that corresponds to thedistraction distance of the knee joint when using distractor 10 asdisclosed herein above to support prosthetic component installation.Condyles of the femoral component couple to articular surfaces 310 and312 of cover 30. Articular surfaces 310 and 312 of cover 300respectively couple to surfaces 62 and 64 of module 32. The firstplurality of load sensors and the second plurality of load sensorgenerate load measurement data that is sent to from module 32 to thecomputer 12 shown in FIG. 1. Typically, computer 12 is in the operatingroom where the surgeon can review the quantitative measurement datawhile performing the knee joint installation. The predeterminedlocations of the first or second plurality of sensors correspond tolocations on articular surfaces 310 and 312. The computer uses load datafrom the load sensors to calculate a load magnitude and a position ofload where a condyle contacts an articular surface and displays it onthe computer in real-time. The load magnitudes, position of load,balance, and alignment of the knee joint should be similar to themeasurement data using distractor 10 of FIG. 1. Further adjustments orrefinements can be made to change a load magnitude, a position of load,balance, or knee joint alignment. Typically, the adjustment can compriserotating a prosthetic component or applying soft tissue release but boneresection is also an option if the measurement data justifies thechange. The changes in quantitative measurement data can be viewed onthe display as the adjustments are made to ensure optimal jointinstallation. The final insert is then placed in the knee joint. Thefinal knee joint should see load magnitudes, position of load, balance,and alignment equal to insert 308. Thus, module 32 is used in distractor10 of FIG. 1 to generate quantitative measurement data to support one ormore bone cuts prior to installation of at least one prostheticcomponent and module 32 is used in an insert 308 to provide quantitativemeasurement data on the prosthetic knee joint.

FIG. 24 is an anterior view of insert 308 installed on a tibialprosthetic component 320 in accordance with an example embodiment.Insert 308 comprises cover 300 coupled to module 32. In one embodiment,tibial prosthetic component 320 includes a tibial tray 322. The tibialtray 322 is configured to align and retain module 32 to tibialprosthetic component 320. In one embodiment, load data is transmittedfrom insert 308 to the computer 12 shown in FIG. 1.

FIG. 25 is a side view of insert 308 installed on the tibial prostheticcomponent 320 in accordance with an example embodiment. Articularsurface 312 of cover 300 has a curved surface that supports coupling toa condyle of a femoral prosthetic component.

FIG. 26 illustrates a step in a knee joint installation procedure inaccordance with an example embodiment. In general, a bone in a kneejoint is prepared to interface with distractor 10 shown in FIG. 1. Inthe example, a tibia 402 is selected for resection. A proximal end of atibia is resected and is prepared to receive a tibial prostheticcomponent. In one embodiment, the proximal end of tibia 402 is cutperpendicular to the tibia anatomical axis using an alignment jig. Forexample, an extramedullary alignment tool can be used align and cut theproximal end of the tibia 402. The resection can also include ananterior-posterior (A-P) slope to the prepared bone surface 404. In oneembodiment an (A-P) slope of 6 degrees slanted posteriorly is made. Thedistal end of femur 400 is left in a natural state.

FIG. 27 illustrates a step of placing distractor 10 in the knee joint ofthe leg in accordance with an example embodiment. A lateral view 412 ofthe leg and a top view of the 410 leg is shown in FIG. 27. In theexample, the leg is placed in extension. The distractor 10 is reduced toa minimum distraction distance and placed on the prepared surface of theproximal end of tibia 402. In general, a distractor, surgical apparatus,or tool as disclosed herein can be coupled to a prepared bone surface, anatural surface, or a prosthetic component. For example, distractor 10can be pinned to a natural tibia for initial support. At the minimumdistraction distance distractor 10 should not require substantial forceto fit within the knee joint. Placing distractor 10 at a minimumdistraction distance is also called zeroing distractor 10. A module 32and a cover 38 are placed on moving support structure 30 as shown inFIG. 1. In one embodiment, a bottom surface of both the moving supportstructure and the fixed support structure contact the prepared bonesurface of tibia 402.

An M-L tilt lock on distractor 10 is then released. The M-L tilt lockreleases moving support structure 30 as shown in FIG. 13 to freelyswivel medially or laterally. In one embodiment, the moving supportstructure 30 cannot tilt when distractor 10 is at the minimum height. Inone embodiment, the knee joint is not stable with distractor 10 zeroed.The knee joint can be supported to prevent the leg from hyperextendingdue to laxity. The distraction distance of distractor 10 is increaseduntil the knee joint does not require support because the knee jointpressure is sufficient to prevent hyperextension when the leg is raisedby supporting the ankle while observing the knee joint pressure mediallyand laterally. Condyles of the femur couple to cover 38 as shown in FIG.3. Module 32 underlying cover 38 measures loading applied to cover 38and transmits the load data to a computer 12 shown in FIG. 1 for furtherprocessing. Distractor 10 also measures and transmits distractiondistance data and M-L tilt angle data to computer 12 shown in FIG. 1.

FIG. 28 illustrates a step of displaying the distraction distance dataand the M-L tilt angle on a display in real-time in accordance with anexample embodiment. A display 14 couples to the computer 12 receivingdistraction distance data and M-L tilt angle data from distractor 10similar to that shown in FIG. 20. The computer 12 provides the M-L tiltangle data and the distraction distance data on display 14 in real-time.Display 14 shows an M-L tilt meter 420 configured to display the M-Ltilt angle of moving support structure 30 as shown in FIG. 1. M-L tiltmeter 420 comprises an indicator bar 422 that indicates medial andlateral tilt. A surgeon at a glance can determine the amount of M-L tiltand whether the M-L tilt is medial or lateral. The value of the medialtilt angle and the lateral tilt angle can also be seen in boxes 426 and428 on display 14. A tilt angle can also be placed in box 424 forincreased visibility to the surgeon. Alternatively, M-L tilt meter 420can have a graduated scale on either side of M-L tilt meter 420 thatallows indicator bar 422 to point to the medial or lateral tilt anglevalue.

Display 14 also shows a bar graph 430 configured to indicate thedistraction distance of distractor 10. A scale 434 indicates thedistraction distance and is adjacent to bar graph 430. A bar 432 in bargraph 430 indicates the distraction distance but the exact distractiondistance can be read by reading the height of bar 432 from scale 434.The distraction distance can also be read from a box 436. Similar to M-Ltilt meter 420, bar graph 430 allows the surgeon to determine thedistraction distance at a glance. In one embodiment, there will two bargraphs, a first bar graph is a measure of a height of the medialcompartment and a second bar graph is a measure of a height of thelateral compartment of the knee joint. Each bar graph can indicatedistance by graph or numeric value.

FIG. 29 illustrates a step of increasing the distraction distance untila predetermined loading is achieved in accordance with an exampleembodiment. In general, a predetermined loading as disclosed hereinabove and below does not imply a specific load value but a value chosenby a user. The predetermined loading can also be within a range orpredetermined range. For example, the predetermined loading can bewithin a range of 20-40 lbs. or 20-60 lbs. for a knee joint. It can varygreatly depending on the musculoskeletal system or the joint systemsurgical apparatus 10 is used on. The user of surgical apparatus 10 willselect the predetermined load value a medial or lateral compartment isset at. Similarly, a predetermined height is a height selected by theuser or within a predetermined range set by the user or a componentmanufacturer. An anterior view 440, a side view 442, and a posteriorview 444 of the knee joint is shown in FIG. 29 to illustrate placementof distractor 10. Fixed support structure 28 couples to the preparedbone surface of the proximal end of tibia 402. Module 32 is placed onmoving support structure 30. Cover 38 couples to module 32. The condylesof femur 400 couple to cover 38. The load applied by the condyles offemur 400 to cover 38 is measured by load sensors in module 32 andtransmitted to computer 12 as shown in FIG. 1.

Knob 26 couples to the distraction mechanism in distractor 10. Rotatingknob 26 increases or decreases the distraction distance of distractor10. In one embodiment, knob 26 is rotated to increase the distractiondistance. Increasing the distraction distance will increase the tensionon the ligaments of the knee thereby increasing the loading applied bythe condyles to cover 38 and thereby module 32. In general, module 32measures the loading applied to cover 38 and is displayed on display 14as shown in FIG. 1. The surgeon increases the distraction distance untila predetermined loading is achieved. The predetermined loadingcorresponds to a known value that supports increased performance andreliability of the knee joint. In the example, moving support structure30 has been released to swing freely medially or laterally. Typically,only one side (medial or lateral) will be distracted to thepredetermined loading. The side not at the predetermined loading will beat a lesser value. The distractor 10 is then locked such that movingsupport structure 30 cannot increase or decrease the distractiondistance.

FIG. 30 illustrates a step of reviewing the position of load, the loadmagnitude, M-L tilt angle, and the distraction distance on display 14 asthe distraction distance of distractor 10 is increased in accordancewith an example embodiment. The description will include components ofFIG. 1 and FIG. 29. The quantitative measurement data is sent tocomputer 12 from distractor 10 and module 32. Display 14 includes a topview of cover 38. Circle 456 and circle 458 represent a location wherethe medial and lateral condyles of femur 400 respectively couple to amedial and lateral side of cover 38. Medial load magnitude data isindicated in box 460 and lateral load magnitude data is indicated in box462. As mentioned previously, moving support structure 30 is allowed tofreely rotate in a medial or lateral direction. Knob 26 is rotated untilthe distraction distance of distractor 10 is increased to thepredetermined loading. In the example, the distraction distance is nolonger increased when the lateral side of cover 38 measures 19 pounds atcircle 458. Note that the loading is not balanced and the medial side ofcover 38 measures 15 pounds at circle 460. Distractor 10 is then lockedto prevent movement of moving support structure 30 shown in FIG. 29. Inone embodiment, the predetermined load on the medial and lateral surfaceof cover 38 is in a range from 20 to 40 pounds.

Tilt meter 420 also shows an imbalance related to the M-L tilt angle ofmoving support structure 30 as shown in FIG. 29. Tilt meter 420indicates the lateral side of moving support structure 30 is higher thanthe medial side. The measured M-L tilt angle is indicated in box 424 andcorresponds to an angle between the plane of moving support structure 30and the plane of fixed support structure 28. In the example, box 424indicates an M-L tilt angle of −4.9 degrees. The distraction distance isalso indicated on display 14. Bar graph 434 illustrates the distractiondistance while box 436 provides a value of the distraction distance. Inthe example, box 436 indicates the distraction distance is 13.1millimeters. In one embodiment, the distraction distance is an averagebecause moving support structure 30 has an M-L tilt angle.

The height of the lateral compartment and the height of the medialcompartment can also calculated from the distraction distance data andthe M-L angle data. In one embodiment, the height of the medialcompartment corresponds to a distance from the prepared bone surface ofthe tibia to the point where the medial condyle couples to the medialside of cover 38. Similarly, the height of the lateral compartmentcorresponds to a distance from the prepared bone surface of the tibia tothe point where the lateral condyle couples to the lateral side of cover38. The height of the medial compartment and the height of the lateracompartment take into account the slope of moving support structure 30.The height of the medial compartment is indicated in box 452 and theheight of the lateral compartment is indicated in box 454. In theexample, the medial gap is 11.5 millimeters and the lateral gap is 14.4millimeters. The difference in the height of the medial compartment andthe height of the lateral compartment corresponds to an offset of thefemur relative to the mechanical axis of the leg.

FIG. 31 illustrates a step of reviewing an x-ray of the leg inaccordance with an example embodiment. The x-ray illustrates a femoraloffset relative to the mechanical axis of the leg. Femur 400 is shown inthe x-ray. A line 470 corresponds to a mechanical axis through femur400. The mechanical axis couples through a center of a femoral head 472to a center of the intercondylar notch of a distal end of femur 400. Anoffset or misalignment of femur 400 from the mechanical axis correspondsto line 474. Line 474 is a line drawn from the center of femoral head472 to a center of the ankle.

Typically, the offset of femur 400 is measured prior to or during a kneereplacement surgery. As shown, lines 470 and 474 can be drawn on thex-ray and the offset can be measured with a protractor or other anglemeasurement device. In one embodiment, the angle formed by lines 470 and474 corresponds to the M-L tilt angle measured in FIG. 30. The offsetmeasured in the x-ray is compared against the M-L tilt angle measured bydistractor 10 as seen in FIG. 1. In general, the M-L tilt angle and theoffset angle measured in the x-ray should be approximately equal.

FIG. 32 illustrates an equalizing step where the M-L angle of movingsupport structure 30 is adjusted in accordance with an exampleembodiment. As mentioned previously, distractor 10 is locked such thatmoving support structure 30 cannot increase or decrease the distractiondistance. Also, moving support structure 30 had been allowed to freelyrotate medially or laterally. In one embodiment, the M-L tilt mechanismof distractor 10 can be engaged to moving support structure 30 and isself-locking when changing an M-L tilt angle. A key, handle, or knob iscoupled to the M-L tilt mechanism to change the M-L tilt angle of movingsupport structure 30. In one embodiment, the key is rotated to adjustthe M-L tilt mechanism. Initially, as indicated in FIG. 30, the M-L tiltangle of moving support structure 30 is −4.9 degrees. Femur 400 with theM-L tilt angle of −4.9 degrees corresponds to a position 480. The key isrotated to adjust the M-L tilt mechanism thereby changing the M-L tiltangle from −4.9 degrees to zero degrees. Changing the M-L tilt anglerotates the femur 400 as indicated by arrow 484 until a position 482 isreached. The position 482 is shown without any further movement in FIG.32 where the M-L tilt angle measured by distractor 10 is zero degrees.It should be noted that the loading on the medial and lateral side ofcover 38 of FIG. 29 can change as well as the position of loading on themedial and lateral side.

FIG. 33 illustrates a step of monitoring equalization of femur 400 ofFIG. 32 on display 14 in accordance of an example embodiment. In oneembodiment, the surgeon can monitor display 14 as the key is rotated onthe M-L tilt mechanism. The surgeon rotates the key until M-L tilt angleis zero. This also corresponds to the condition where the plane of fixedsupport structure 28 of FIG. 32 and the plane of moving supportstructure 30 are parallel to one another. Note that the averagedistraction distance as indicated in box 436 does not change. The medialgap as indicated in box 452 and the lateral gap as indicated by box 454does change because the M-L tilt has changed to zero. The medial gapindicated in box 452 reads 12.9 millimeters and the lateral gapindicated in box 454 reads 13.2. Referring briefly to FIG. 31, the stepof equalizing moves the center of the femoral head 472 medially as shownin FIG. 32. Note on FIG. 31 that moving the center of the femoral head427 medially reduces the offset angle formed by lines 470 and 474thereby placing the leg in better alignment. In general, the step ofequalizing eliminates or reduces the offset of the femur 400 to anacceptable alignment based on clinical evidence.

Alternatively, referring to FIGS. 27-35, distractor 10 respectivelycouples a support structure 30 to femur 400 and a support structure 28to a tibia 402. Femur 400 and tibia 402 can have natural surfaces orprepared bone surfaces. In the example, distractor 10 is configured tosupport at least one bone cut to femur 400 for an installation of afemoral prosthetic component that is in alignment, loaded correctly, andbalanced. In one embodiment, fluoroscope images, CT scans, MRI, or otherassessment techniques can be used prior to surgery and in surgery toprovide information related to alignment, loading, balance, contactpoint, contact point rotation to support the one or more bone cut toachieve an optimal outcome. The leg is placed in a first predeterminedpose. In one embodiment, the leg is placed in extension. Distractor 10is inserted into a knee joint and knob 26 in a minimum heightconfiguration. Distraction mechanism 24 is configured to increase ordecrease a distance between support structures 28 and 30 by rotatingknob 26. Distraction mechanism 24 is rotated until a predetermined loadvalue is measured by distractor 10 and indicated on the computerreceiving the quantitative measurement data. Typically, a single side(medial or lateral) of measurement module 32 will measure thepredetermined load value while the remaining side will not be at thepredetermined load value. Also, support structure 30 will be at a firsttilt relative to support structure 28. In one embodiment, the tilt ofsupport structure 30 corresponds to a difference in heights of themedial and lateral compartments being distracted. The computer willdisplay the tilt value of support structure 30 and load values on themedial and laterals sides of measurement module 32 in real time. Asmentioned herein above, the medial and lateral compartment heights arealso measured and displayed on the display. Tilt mechanism 22 is thenadjusted under user control such that the medial and lateral sides areloaded equally. Adjusting tilt mechanism 22 changes a position ofsupport structure 30 from the first tilt to a second tilt. The medialand lateral compartment heights change on the display of the computer assupport structure 30 changes to the second tilt. In one embodiment, abone cut is subsequently made to the femur that corresponds to thesecond tilt that yields the predetermined load value. It should be notedthat the example sets the load values on the medial and lateralcompartments equal. The medial and lateral compartments can be set todifferent load values if desired. In one embodiment, the final insertcoupling to the femoral prosthetic component in a prosthetic knee jointcomprises a surface of equal heights on the medial and lateral sides.Cutting a portion of the distal end of the femur related to the secondtilt compensates for differences in height for balanced loading measuredby distractor 10 when using the final insert having equal medial andlateral heights for the leg in extension. As mentioned previously, otherbone cut compensation can also be added with or to the second tilt valueto adjust for defects, alignment issues, or other anomalies found in theassessments prior to surgery. Although described for distractor 10, theuse applies to all surgical apparatus disclosed herein as they alloperate similarly.

FIG. 34 illustrates a step of drilling guide holes in femur 400 inaccordance with an example embodiment. As disclosed in FIG. 32 and FIG.33, distractor 10 the height of the medial compartment and the height ofthe lateral compartment have been made equal. Equalizing the medial andlateral compartment heights eliminates or reduces the femoral offsetrelative to the mechanical axis of the leg such that the leg is inalignment. Moving support structure 30 has been locked to preventmovement or change of the distraction distance. The medial compartmentheight and the lateral compartment height having an M-L tilt angle ofzero are also locked in place. In one embodiment, the M-L tilt mechanismis self-locking. The knob coupled to the M-L tilt mechanism has beenremoved so the M-L tilt angle cannot be changed. Adjustments to changethe applied loading to the medial or lateral surface of cover 38 areperformed prior to drilling guide holes. For example, soft tissuerelease can be performed to adjust the load values.

Femur 400 is in alignment with the mechanical axis having the height ofthe medial compartment equal to the height of the lateral compartment.The load and position of load on the medial side and the lateral side ofcover 38 have been quantitatively measured and verified withinacceptable predetermined ranges for the prosthetic knee joint system.The measured distraction height relates to a thickness of an installedfinal tibial prosthetic component, a final insert, and a final femoralprosthetic component. Thus, femur 400 guide pin holes can be drilled toalign and support a resection guide for the distal end of femur 400. Adrill guide holder 490 is coupled to distractor 10. A drill guide 492couples to drill guide holder 490. Drill guide holder 490 aligns andretains drill guide 492 adjacent to the distal end of femur 400. Drillguide 492 includes one or more openings 496 that receive a drill bit 494to drill openings in the distal end of femur 400.

FIG. 35 illustrates a step of removing drill guide 492 and drill guideholder 490 of FIG. 34 from distractor 10 in accordance with an exampleembodiment. Holes 500 are drilled using drill guide holder 490 and drillguide 492 coupled to distractor 10 as shown in FIG. 34. Holes 500 willsubsequently be used to couple a resection guide to femur 500 and makeone or more cuts for fitting a femoral prosthetic component to thedistal end of femur 400.

FIG. 36 illustrates a step of reducing the distraction distance ofdistractor 10 and placing the leg in flexion in accordance with anexample embodiment. The M-L tilt mechanism is released allowing movingsupport structure 30 to freely swing medially or laterally. Distractor10 is adjusted to a minimum distraction distance. In one embodiment, theminimum distraction distance occurs when both fixed support structure 28and moving support structure 30 couple to the prepared surface at theproximal end of tibia 402. As mentioned previously, the plane of fixedsupport structure 28 corresponds to zero degrees M-L tilt. In oneembodiment, the minimum distraction distance is 6.8 millimeters. The legcan be placed in flexion where tibia 402 and femur 400 form a 90 degreeangle. In one embodiment, module 32 includes an inertial sensorconfigured to measure the angle between femur 400 and tibia 402. Theinertial sensor data is transmitted to the computer and can be displayedon display 14.

Display 14 is shown with tilt meter 420 and bar graph 430. Tilt meter420 indicates an M-L tilt angle of zero degrees. Since moving supportstructure 30 can swing freely medially or laterally it couples to theprepared surface of tibia 402 with fixed support structure 28. Thus,both are coupled to the same plane and the M-L tilt angle is zerodegrees. The M-L tilt mechanism was enabled in FIG. 32 and adjusted toequalize the medial and lateral gap such that the M-L tilt angle iszero. The M-L tilt angle of 0.0 degrees is indicated in box 424. The bargraph 430 indicates a minimum distraction distance on bar 432. Theminimum distraction distance of 6.8 millimeters is shown in box 436.

FIG. 37 illustrates a step of adjusting the distraction distance whilethe leg is in flexion in accordance with an example embodiment. The stepof adjusting the distraction distance is similar to when the leg was inextension. Distractor 10 of FIG. 36 is adjusted to increase thedistraction distance from the minimum distraction distance. The loadingon the medial and lateral sides of cover 38 of FIG. 36 will increase asthe distraction distance increases. In one embodiment, the surgeon isviewing the load magnitude on display 14 as the distraction distance isincreased. This is indicated in box 460 and box 462 on display 14showing the position of load on the medial and lateral surface of cover38. The distraction distance is increased until the loading on cover 38reaches a predetermined value. Note that the values on the medial andlateral sides of cover 38 are not equal under flexion but the maximumload value corresponds to the desired predetermined value.

The moving support structure of FIG. 36 was released from the M-L tiltmechanism to allow it to freely swing medially or laterally when inflexion. M-L tilt meter 420 indicates the M-L tilt angle and the valueis displayed in box 424 as −4.9 degrees. The distraction distance isalso displayed in bar graph 430 and the value of 13.1 millimeters isdisplayed in box 436. The distraction distance is an average distance.The height of the medial compartment and the height of the lateralcompartment is calculated by computer 12 of FIG. 1 using the measurementdata such as the M-L tilt angle, the position of load, and distractiondistance. The height of the medial compartment is measured as 11.5millimeters as shown in box 452 of display 14. The height of the lateralcompartment is measured as 14.4 millimeters as shown in box 454 ofdisplay 14. The measurement data listed herein above can be stored inmemory of computer 12 shown in FIG. 1.

FIG. 38 illustrates a step of equalizing the height of the medialcompartment and the height of the lateral compartment with the leg inflexion in accordance with an example embodiment. The distractionmechanism is locked to prevent movement of moving support structure 30of FIG. 36. The M-L tilt mechanism is engaged to adjust the M-L tiltangle of moving support structure 30. As mentioned previously, M-L tiltmechanism is self-locking. The M-L tilt angle is adjusted to equalizethe M-L tilt angle to zero degrees with the leg in flexion. Adjustingthe M-L tilt angle to zero degrees equalizes the height of the medialand lateral compartments with the leg in flexion. Similar to FIG. 31 anoffset of the leg alignment in flexion is reduced when the medial gapand the lateral gap equalized. The loading on the medial and lateralsides of cover 38 is viewed on display 14 and adjusted if the loading istoo high or the balance is significantly off. Typically, soft tissuerelease is used to adjust the loading and balance.

After adjustments have been made under equalized conditions thedistraction mechanism lock is released and the M-L tilt mechanism isdisengaged to allow moving support structure 30 to freely rotatemedially and laterally. Measurement data should indicate that the medialand lateral gap are closer than was previously measured in flexion. Themeasurement data should also indicate the medial and lateral sides arein better balance and the load magnitude is within a predetermined rangethat supports performance and reliability of the knee joint. In theexample, the medial gap is listed in box 452 as 11.5 millimeters. Thelateral gap is listed in box 454 as 12.7 millimeters. The differencebetween the applied load between the medial and lateral sides is 1 lband the highest load magnitude is 15 lbs on the lateral side of cover38. The difference in the gap height between the knee joint in extensionand the knee joint in flexion can be due to knee geometry or position ofapplied load on cover 38. The gap data, load data, balance data, and M-Ltilt angle is stored in memory on computer 12 as shown in FIG. 1. Itshould be noted that the values disclosed herein above for the knee inextension and flexion can vary significantly from the data disclosed andis only used as an example.

FIG. 39 illustrates a step of placing a sizer 510 on distractor 10 tosupport selection of a femoral prosthetic component in accordance withan example embodiment. Selecting a correct size for the femoralprosthetic component minimizes overhang of the femoral prostheticcomponent, minimizes bone resection, and maximize coverage usingalgorithms to determine an optimal installation for different models ofthe femoral prosthetic component. Previously, the leg was equalized andadjusted in flexion using quantitative measurement information frommodule 32 and distractor 10 as shown in FIG. 36. A sizer 510 isconfigured to couple to distractor 10 with the leg in flexion. In theexample embodiment, tibia 402 is at approximately a 90 degree angle tofemur 400. The exact angle can be quantitatively measured with aninertial sensor in module 32. Sizer 510 comprises a fork 520, a femurcoupler, a threaded cylinder 518, a spring 512, a knob 516, and a scale514. Fork 520 includes one or more retaining features that align andretain fork 520 to distractor 10. Threaded cylinder 518 extends fromfork 520 above femur 400 in flexion. Spring 512 overlies threadedcylinder 518 and is supported by fork 520. The femur coupler couples tothe threaded cylinder 518 and femur 400. In one embodiment, threadedcylinder 518 couples through an opening of the femur coupler such that aportion of the femur coupler is supported by spring 512. The femurcoupler also couples to a location on femur 400. Knob 516 threads ontothreaded cylinder 518 and couples to the femur coupler. Spring 512provides resistance against the femur coupler and knob 516. Scale 514 isformed on threaded cylinder 518 and is visible above a top surface ofknob 516. Scale 514 is used to select a femoral prosthetic componentsize.

FIG. 40 illustrates a step of coupling a femur coupler 521 to femur 400with the leg in flexion in accordance with an example embodiment. Femurcoupler 521 comprises a body 522 and an extension 524. Body 522 extendsfemur coupler 521 from threaded cylinder 518 over femur 400. Extension524 extends from body 522 and couples to femur 400. In one embodiment,extension 524 includes at least one bend that supports coupling to femur400 without body 522 coupling to femur 400. Extension 524 can couple toa predetermined location on femur 400 or a bone landmark of femur 400.As mentioned previously scale 514 can be read above a surface of knob514 to support selection of the femoral prosthetic component.

FIG. 41 illustrates a step of providing a plurality of sizers 550 tosupport selection of the femoral prosthetic component. In oneembodiment, four different sizers are provided to select the femoralprosthetic component that best fits the knee joint. A sizer 530 islabeled SY and includes a scale 540. A sizer 532 is labeled BM andincludes a scale 542. A sizer 534 is labeled SN and includes a scale544. A sizer 536 is labeled ZM and includes a scale 546. The scales 540,542, 544, and 546 are all different and support selection of the femoralprosthetic component. Sizers 530, 532, 534, and 536 can have one or moredrill guide holes configured to support drilling holes in the distal endof the femur 400.

FIG. 42 illustrates a step of drilling one or more holes in the distalend of femur 400 in flexion in accordance with an example embodiment.The one or more holes will be used to align or support a cutting guideconfigured to prepare a surface of the femur 400. The leg is in flexionhaving femur 400 and tibia 402 at approximately a 90 degree angle.Distractor 10 has been used to equalize the knee joint, align the leg,and the load magnitudes have been adjusted if needed. A sizer 510 hasbeen selected as providing the best fit for femur 400. Sizer 510 has oneor more drill guides 550 for receiving a drill bit 552 to drill femur400. A drill using drill bit 552 is used to drill a hole in femur 400using drill guide 550.

FIG. 43 illustrates one or more holes drilled in the distal end of thefemur in accordance with an example embodiment. Holes 554 are drilled inthe distal end of the femur to support the cutting guide for preparing abone surface of the femur 400 for receiving the femoral prostheticcomponent. Distractor 10 and sizer 510 of FIG. 42 were used to drillholes 554 at predetermined locations. The distractor 10 is removed fromthe knee joint.

Bone surfaces of the distal end of femur 400 are prepared and thefemoral prosthetic component is installed. Similarly, the tibialprosthetic component can be installed. Module 32 can be installed in aninsert 308 as disclosed in FIG. 24 and FIG. 25. Insert 308 can beinstalled in the knee joint such that insert 308 is coupled to andretained by the tibial prosthetic component. The knee joint can be movedthrough a range of motion for the surgeon to gain subjective feedback onthe knee joint installation. Module 32 will send quantitativemeasurement data to the computer 12 as shown in FIG. 1 for furtherevaluation. In general, module 32 should provide similar measurementdata as generated in flexion and extension using distractor 10. In oneembodiment, computer 12 checks the measurement data from insert 308 andcompare it to the previously measured data using distractor 10. Thus,module 32 and insert 308 can be used to verify proper installation ofthe knee joint. Moreover, fine adjustments can be made to furtherimprove the joint installation prior to finalizing the installation. Theinsert 308 is then removed and a final insert equal in size is insertedto complete the knee joint installation.

Alternatively, referring to FIGS. 36-43, distractor 10 respectivelycouples a support structure 30 to femur 400 and a support structure 28to a tibia 402 in a second predetermined pose. As shown, the leg isplaced in flexion at a 90 degree angle. Femur 400 and tibia 402 can havenatural surfaces or prepared bone surfaces. In the example, distractor10 is configured to support at least one bone cut to femur 400 for aninstallation of a femoral prosthetic component that is in alignment,loaded correctly, and balanced in flexion. In one embodiment,fluoroscope images, CT scans, MRI, or other assessment techniques can beused prior to surgery and in surgery to provide information related toalignment, loading, balance, contact point, contact point rotation tosupport the one or more bone cut to achieve an optimal outcome inflexion. The leg is placed in the second predetermined pose anddistractor inserted after being placed in the minimum heightconfiguration. Distraction mechanism 24 is configured to increase ordecrease a distance between support structures 28 and 30 by rotatingknob 26. Distraction mechanism 24 is rotated until a predetermined loadvalue is measured by distractor 10 and indicated on the computerreceiving the quantitative measurement data in flexion. Typically, asingle side (medial or lateral) of measurement module 32 will measurethe predetermined load value while the remaining side will not be at thepredetermined load value in flexion. Also, support structure 30 will beat a first tilt relative to support structure 28 in flexion. In oneembodiment, the tilt of support structure 30 corresponds to a differencein heights of the medial and lateral compartments being distracted inflexion. The computer will display the tilt value of support structure30 and load values on the medial and laterals sides of measurementmodule 32 in real time. As mentioned herein above, the medial andlateral compartment heights are also measured and displayed on thedisplay in flexion. Tilt mechanism 22 is then adjusted under usercontrol such that the medial and lateral sides are loaded equally inflexion. Adjusting tilt mechanism 22 changes a position of supportstructure 30 from the first tilt to a second tilt in flexion. The medialand lateral compartment heights change on the display of the computer assupport structure 30 changes to the second tilt in flexion. In oneembodiment, a bone cut is subsequently made to the femur thatcorresponds to the second tilt that yields the predetermined load valuein flexion. It should be noted that the example sets the load values onthe medial and lateral compartments equal in flexion. The medial andlateral compartments can be set to different load values if desired inflexion. In one embodiment, the final insert coupling to the femoralprosthetic component in a prosthetic knee joint comprises a surface ofequal heights on the medial and lateral sides. Cutting a second portionof the distal end of the femur related to the second tilt in flexioncompensates for differences in height for balanced loading measured bydistractor 10 when using the final insert having equal medial andlateral heights for the leg in extension. In one embodiment, the cut ofthe second portion of the distal end of the femur is designed to workwith the cut of the first portion of the distal end of the femur toallow optimal loading, balance, and alignment over the full range ofmotion of the leg with the femoral prosthetic component, final insert,and tibial prosthetic component. All the quantitative measurements takenusing distractor 10 translates to the final knee prosthetic componentinstallation. As mentioned previously, other bone cut compensation canalso be added with or to the second tilt value to adjust for defects,alignment issues, or other anomalies found in the assessments prior tosurgery. Although described for distractor 10, the use applies to allsurgical apparatus disclosed herein as they all operate similarly.

FIG. 44 is an illustration of a distractor 1000 in accordance with anexample embodiment. Referring briefly to FIG. 1 distractor 10 isconfigured to distract a knee joint, transmit measurement data to aremote system such as a computer 12, and display the measurement data inreal-time on display 14 in an operating room. Distractor 1000 is analternate embodiment of distractor 10. Distractor 1000 can be usedsimilarly to distractor 10 as disclosed herein above. Distractor 1000can include one or more sensors to measure distraction height,medial-lateral angle, load magnitude applied by the musculoskeletalsystem to the distractor, leg position, support one or more bone cuts,support alignment, and measure position of load applied to the medialand lateral surfaces of the distractor.

Referring back to FIG. 44, the distractor 1000 comprises a housing 600,a fixed plate 602, lateral plate 604 (for a knee joint of a left leg), amedial plate 606 (for the knee joint of the left leg), a lateral brake608, a medial brake 610, a knob 616, a lateral height scale 614, and amedial height scale 612. Knob 616 is used to raise and lower lateralplate 604 and medial plate 606 in relation to fixed plate 602. Fixedplate 602 couples to a prepared surface of a tibia. In one embodiment,knob 616 is rotated counter clockwise or clockwise to raise or lowerplates 604 and 606. The amount of lateral distraction and medialdistraction can be respectively read off of lateral scale 614 and medialscale 612 on housing 600. One or more magnetic height sensors can beused to measure the lateral and medial distraction heights as disclosedherein above. The electronic circuitry as disclosed in FIG. 15 iscoupled to the one or more magnetic height sensors and placed withinhousing 600 to control a measurement process and transmit the heightdata to be displayed on a display within the operating room. Distractor1000 can be used in a knee joint of the right leg with the knowledgethat the medial and lateral sides of distractor 1000 are transposed.Alternatively, a second distractor could be provided for a right leg.Note that distractor 1000 has plates 604 and 606 offset. The offsetsupports placement of the patella on a lateral side of the knee jointand allows the patella to be placed back on the knee joint afterdistractor 1000 is inserted. The patella loads the knee joint which istaken into account in all the measurement data and subsequent stepstaken prior to the knee joint installation. The second or right legdistractor provided with distractor 1000 would have an opposite offsetto support placement of the patella laterally on the right knee jointprior to installation of the second distractor.

Distractor 1000 is configured to distract, equalize, and supportalignment of a leg to the mechanical axis of the leg by one or more bonecuts to the femur. The bone cuts to a distal end of the femur supportinstallation of a femoral prosthetic component that aligns the femur andtibia to the mechanical axis. Distractor 1000 is used to drill guideholes for a cutting jig with the leg in extension and flexion. Thecutting jig is then coupled to the distal end using the guide holes andthe bone cuts are made. In general, distractor 1000 is configured togenerate an offset on the prepared surfaces of the distal end of thefemur that reduces or eliminates a varus or vargus leg deformity thatsupports an installation of a prosthetic knee joint in alignment to themechanical axis of the leg.

FIG. 45 is an illustration of the distractor 1000 with a transparenthousing to illustrate components therein in accordance with an exampleembodiment. Knob 616 is configured to rotate to raise and lower slideblock 620. In one embodiment, a threaded shaft extends from knob 616.The threaded shaft is aligned and retained by a structure 626 formed inhousing 600. In one embodiment, structure 626 can have an opening with abearing surface. The threaded shaft can have a region that is notthreaded that couples to the bearing surface of structure 626 to supportalignment of the threaded shaft within housing 600 and rotation of thethreaded shaft. Alternatively, structure 626 can have a threaded openingfor receiving the threaded shaft. Slide block 620 includes a threadedopening configured for receiving the threaded shaft coupled to knob 616.In one embodiment, slide block 620 is not fastened to housing 600whereas structure 626 is attached or integrated as part of housing 600.Thus, rotating knob 616 can raise or lower slide block 620 in relationto structure 626 but only slide block 620 can move in relation tohousing 600.

Slide block 620 is housed within housing 600 and includes a free wheelgear 618. In one embodiment, free wheel gear 618 is located at aproximal end of slide block 620 and configured to rotate. A post 622extends from lateral plate 604 and is configured to move parallel toslide block 620 and the threaded shaft. Post 624 has gear teeth engagingwith free wheel gear 618. Similarly, a post 624 extends from medialplate 606 and is configured to move parallel to slide block 620 and thethreaded shaft. Post 622 has gear teeth engaging with free wheel gear618. Posts 622 and 624 extend through openings in a proximal end ofhousing 600 into an interior of the housing. Housing 600 aligns,retains, and supports movement of lateral plate 606 and medial plate604. In one embodiment, grooves are formed in posts 622 and 624. Housing600 has corresponding tongues 628 that fit within the grooves that alignand retain post 622 and post 624 to the housing. Tongues 628 extendingfrom an interior surface of housing 600 are received within the groovesof posts 622 and 624 and are configured to support movement parallel tothe threaded shaft and slide block 620.

In the illustration, knob 616 cannot be rotated clockwise as slide block620 contacts structure 626 whereby no gap exists to allow furtherrotation or the threaded shaft. In this position, lateral plate 606 andmedial plate 604 are in a minimum height position corresponding tolateral plate 606 and medial plate 604 contacting fixed plate 602. Fixedplate 602 is coupled to housing 600. In one embodiment, fixed plate 602extends from housing 600 and is molded or machined as part of housing602. Fixed plate 602 can be at a 90 degree angle relative to themovement of post 622, post 624, slide block 620, and the threaded shaft.

Brakes 608 and 610 respectively prevent movement of post 622 and post624. In one embodiment, brakes 608 and 610 are friction brakes. Brakes608 or 610 can include a threaded shaft 632. The threaded shaft 632 ofbrakes 608 or 610 couples through a threaded opening 630 formed inhousing 600. Rotating threaded shaft 632 in opening 630 clockwise orcounter clockwise can respectively increase or decrease the depth ofthreaded shaft 632 within housing 600. In one embodiment, threaded shaft632 of brake 608 contacts and applies pressure to post 622 as brake 608is rotated clockwise. The pressure applied to post 622 presses tongues628 against the corresponding grooves on post 622. The friction createdbetween tongues 628 and post 622 by brake 608 prevents movement of post622 and thereby lateral plate 604. Similarly, threaded shaft 632 ofbrake 610 can be rotated to contacts and apply pressure to post 624 asbrake 610 is rotated clockwise. The pressure applied to post 624 pressestongues 628 against the corresponding grooves on post 624. The frictioncreated between tongues 628 and post 624 by brake 610 prevents movementof post 624 and thereby medial plate 606. Conversely, rotating brakes608 and 610 counter-clockwise where brakes 608 and 610 do notrespectively contact posts 622 and 624 allows posts 622 and 624 to movewithout friction.

FIG. 46 illustrates a step in a knee joint installation procedurerelated to distractor 1000 shown in FIG. 44 in accordance with anexample embodiment. The listing of the steps herein below does not implyany order or sequence. Distractor 1000 is placed in the knee jointsimilar to that shown in FIG. 1. A proximal end of the tibia has aprepared surface and the leg is positioned in extension. The fixedposition plate 602 couples to the prepared surface of tibia. Theproximal end of tibia can be cut perpendicular to the tibia anatomicalaxis using an alignment jig. The resection of tibia can also include ananterior-posterior (A-P) slope.

A computer receives transmitted measurement data from distractor 1000.Referring back to FIG. 46 load sensors (not shown) can be embedded inmedial plate 606 and lateral plate 604 to support measurement of a loadmagnitude and position of load applied to plates 604 and 606.Alternatively, the load sensors can comprise a module that rests on asurface of medial plate 604 or lateral plate 606. Distractor 1000 canalso include one or more magnetic sensors configured to measure adistraction distance between lateral plate 604 and fixed plate 602 asdisclosed herein above. The one or more magnetic sensors can also beconfigured to measure a distraction distance between medial plate 606and fixed position plate 602. The distraction distance data and the loadmeasurement data is transmitted to the computer for further processing.In one embodiment, the load sensors and the one or more magnetic heightsensors couple to electronic circuitry such as shown in FIG. 15. Theelectronic circuitry of FIG. 15 is configured to control a measurementprocess and transmit measurement. The electronic circuitry and the oneor more magnetic height sensors can be housed in housing 600 ofdistractor 1000. The load measurement data received by the computer canbe used to calculate the load magnitude and the position of load appliedto lateral plate 604 and medial plate 606. The load magnitude and theposition of load can be displayed on a display coupled to the computerin real-time to the surgeon in the operating room. Similarly, thedistraction height measurement data related to the lateral plate 604 andthe medial plate 606 received by the computer can be displayed on thedisplay. The distraction height measurement data can also be used tocalculate a medial-lateral slope between lateral plate 604 and medialplate 606. The slope would correspond to a line through contact point(e.g. position of load) on the lateral plate 604 and the medial plate606.

In the illustration, distractor 1000 is placed in the knee joint. Thenatural femur 700 is shown having a medial condyle 704 and a lateralcondyle 702 respectively overlying the lateral plate 604 and the medialplate 606. Distractor 1000 is inserted in a minimum distraction height.As mentioned previously, the minimum distraction height corresponds tothe lateral plate 604 and the medial plate 606 coupling to the fixedposition plate 602. Brakes 608 and 610 are not enabled for respectivelypreventing movement of lateral plate 604 and medial plate 606.

FIG. 47 illustrates a step in the knee joint installation procedurerelated to distractor 1000 wherein knob 616 is rotated counter clockwisein accordance with an example embodiment. The direction of rotation ofknob 616 is indicated by arrow 706. Rotating knob 616 counter clockwiserotates threaded shaft 710 such that slide block 620 moves away fromstructure 626. In the example, lateral plate 604 and medial plate 606are unloaded and posts 622 and 624 are free to move. Slide block 620moves in a direction indicated by arrow 708. In the unloaded state,slide block 620 moves both lateral plate 606 and medial plate 604equally in the direction indicated by arrow 708. A distraction heightcorresponds to the separation between lateral plate 604 or medial plate606 and fixed position plate 602. The distraction height is indicated bydouble sided arrow 712 and is labeled H. As mentioned, medial plate 606is raised simultaneously with lateral plate 604 and by an equal amountfrom fixed position plate 602. The distraction data from magneticdistance sensor can be transmitted to the computer and the distractiondistance H can be displayed on the display of the computer within theoperating room to review the distraction distance in real-time. Notethat the lateral condyle 702 and the medial condyle 704 are not incontact with lateral plate 604 or medial plate 606.

FIG. 48 illustrates a step in the knee joint installation procedurerelated to distractor 1000 coupling to femur 700 in accordance with anexample embodiment. As mentioned previously, fixed position plate 602rests against a prepared surface of a tibia (not shown). Brakes 608 and610 are not enabled thereby allowing posts 622 and 624 to move freely.Knob 616 rotates threaded shaft 710 counter clockwise to increase a gapbetween slide block 620 and structure 624 as indicated by arrow 708.Slide block 620, post 622, and post 624 are motivated by threaded shaft710 to raise lateral plate 604 and medial plate 606 thereby increasing adistraction height as indicated by double sided arrow 712. Lateral plate604 and medial plate 606 move simultaneously and by the same amount. Inthe example, lateral condyle 702 contacts lateral plate 604. In oneembodiment, load sensors coupled to lateral plate 604 would register ameasureable load as lateral condyle 702 couples to lateral plate 604.The load measurement data can be displayed on the display coupled to thecomputer receiving the load measurement data. Note that medial plate 606is not in contact with medial condyle 704. In one embodiment, thecounter clockwise rotation of knob 616 continues until a predeterminedload magnitude is reached applied by lateral condyle 702 to lateralplate 604. As mentioned, the change in load magnitude can be viewed onthe display in real-time. Typically, the predetermined load magnitudecan be within a predetermined load magnitude range that has beenclinically proven to provide performance, reliability, and longevity ofthe prosthetic knee joint.

FIG. 49 illustrates the step in a knee joint installation procedurerelated to distractor 1000 where lateral plate 604 and medial plate 606contact femur 700 in accordance with an example embodiment. Aspreviously stated, the lateral plate 604 is in contact with lateralcondyle 702 and distracted to a predetermined load magnitude. Thelateral plate 604 measuring the predetermined load magnitude alsocorresponds to a predetermined distraction distance. Brake 608 isrotated clockwise to contact post 622 to prevent any further movement oflateral plate 604. Brake 610 is not enabled and post 624 is free to moveas slide block 620 moves.

Knob 616 is rotated counter clockwise to increase the gap between slideblock 620 and structure 626. Brake 608 prevents post 622 from moving butfree wheel gear 618 rotates clockwise as threaded shaft 710 is rotatedcounter clockwise. Free wheel gear 618 engages with the gear teeth ofpost 624 as it rotates clockwise. The clockwise rotation of free wheelgear 618 increases the distraction distance between medial plate 606 andfixed position plate 602. Thus, lateral plate 604 does not move whilethe distraction distance between medial plate 606 and fixed positionplate 602 increases until medial plate 606 contacts medial condyle 704of femur 700. Similar to lateral plate 604, load sensors coupled tomedial plate 606 would register a measureable load as medial condyle 704contacts medial plate 606. Loading and position of load on medial plate606 is displayed on the display coupled to the computer receiving theload measurement data. In one embodiment, knob 616 is rotated counterclockwise to increase the load magnitude applied to medial plate 606until it is equal to the load magnitude applied to lateral plate 604(e.g. the predetermined load magnitude). Thus, the tension of medialcollateral ligament is the same as the lateral collateral ligament.

FIG. 50 illustrates a step in the knee joint installation procedurerelated to distractor 1000 where equalization of the medial gap and thelateral gap occurs in accordance with an example embodiment. In general,the medial gap is the distraction distance in the medial compartment ofthe knee joint. Similarly, the lateral gap is the distraction distancein lateral compartment of the knee joint. Referring briefly to FIG. 49,the medial gap is larger than the lateral gap but both are set such thatthe tension of the medial collateral ligament is the same as the lateralcollateral ligament.

Referring back to FIG. 50, brake 610 is enabled to prevent movement ofpost 624. Conversely, brake 608 is released whereby post 622 can movefreely to increase or decrease the distraction distance between lateralplate 604 and fixed position plate 602. In the example, the lateral gapis smaller than the medial gap. Thus, a process of equalizing the medialand lateral gaps corresponds to increasing the lateral gap. Knob 616 isrotated counter clockwise as indicated by arrow 706. Knob 616 rotatesthreaded shaft 710 counter clockwise to increase the distance betweenslide block 620 and structure 626. Free wheel gear 618 rotates counterclockwise by engagement with the gear teeth of post 624 in a fixedposition (e.g. locked by brake 610) as slide block 620 moves asindicated by arrow 708. The counter clockwise rotation of free wheelgear 618 moves post 622 in a direction indicated by arrow 714 as thegear teeth of post 622 engages with free wheel gear 618. As mentioned,brake 608 is disabled allowing post 622 to move as free wheel gear 618rotates.

The distraction distance between lateral plate 604 and fixed positionplate 602 is increased until the lateral gap is the same as the medialgap. Increasing the medial gap increases the tension on the medialcollateral ligament. Conversely, the tension on the medial collateralligament is not raised significantly because medial plate 606 does notmove. In one embodiment, soft tissue release can be practiced on thelateral collateral ligament to reduce the tension and equalize thetensions between the medial collateral ligament and the lateralcollateral ligament. Load sensors coupled to medial plate 606 andlateral plate 604 provide load measurement data to the computer wherebythe load magnitude data applied to medial plate 606 and lateral plate604 can be viewed in real-time. Thus, the soft tissue release can beperformed until the load magnitude on medial plate 606 and the lateralplate 604 are the same which corresponds to approximately equal lateraland medial collateral ligament tension. Alternatively, the soft tissuerelease can be performed to set different loadings in each compartmentrelative to one another. Equalizing the medial and lateral gap isdisclosed in FIG. 31 whereby the process of equalization reduces thetotal error of the femur and tibia in relation to the mechanical axis ofthe leg as discussed herein above for distractor 10.

In general, the prepared surface of the tibia is resected to align thetibia to the mechanical axis. Note that the distal end of the femur isforcibly aligned to have equal medial and lateral gaps at substantiallyequal loading in each compartment of the knee which is the process ofequalizing or equalization of the knee joint for receiving knee jointprosthetic components. In one embodiment, a guide hole jig can becoupled to distractor 1000 or to the distal end of the femur fordrilling guide holes for a bone cutting jig. The guide holes are drilledto align the cutting jig to cut one or more surfaces of the distal endof the femur to produce the equalized knee compartments. The guide holesare drilled at an angle that counters offset of the femur relative tothe mechanical axis whereby a prepared surface of the distal end of thefemur cut by the femoral cutting jig coupled to the guide holes producesan installed femoral prosthetic component that is aligned to themechanical axis.

Brake 610 can be released after drilling the guide holes for theequalization process using distractor 1000. Knob 616 can then be rotatedclockwise to bring the lateral plate 604 and medial plate 606 to aminimum height. The leg can then be placed in flexion. For example, theleg can be placed where the tibia is at a 90 degree angle relative tothe femur. A similar process to that disclosed herein above usingdistractor 1000 can be used to equalize the compartments in flexion. Inone embodiment, with the leg in flexion, knob 616 is rotated counterclockwise to raise lateral plate 604 and medial plate 606 into contactwith a posterior portion of the lateral condyle and a posterior portionof the medial condyle. Knob 616 is rotated counter clockwise until apredetermined load magnitude is measured. The load magnitude on themedial and lateral condyles can be viewed on the display coupled to thecomputer in real-time that receives load measurement data. Typically, asingle condyle will be at the predetermined load magnitude.

The brake is applied to the side that measures the predetermined loadmagnitude. For example, lateral plate 604 measures at the predeterminedload magnitude and brake 608 is applied. Medial plate 606 is free tomove by rotation of knob 616. Knob 616 is rotated counter clockwise toincrease the distraction distance between medial plate 606 and fixedposition plate 602 thereby increasing the load magnitude applied tomedial plate 606. The increase in load magnitude and the distractiondistance is displayed on the display coupled to the computer receivingload measurement data and distraction distance data. In one embodiment,the distraction distance between medial plate 606 and fixed positionplate 602 is increased until the predetermined load magnitude ismeasured. Thus, the load magnitude on medial plate 606 and lateral plate604 are equal to the predetermined load magnitude. The height of themedial compartment and the height of the lateral compartment can bedifferent at the predetermined load magnitude. For example the lateralcompartment height can be greater than the lateral compartment height.

Brake 608 is released with the load magnitude applied to the medialplate 606 equal to the load magnitude applied to the lateral plate 604.Brake 610 is enabled such that medial plate 606 cannot move. Knob 606 isrotated counter clockwise to increase the distraction distance betweenmedial plate 604 and fixed position plate 602. The distraction distanceis increased until the lateral compartment height is equal to the medialcompartment height. Increasing the distraction distance between lateralplate 604 and fixed position plate 602 will increase the tension on thelateral collateral ligament. After the medial compartment height and thelateral compartment height are equalized in flexion the tension on thelateral collateral ligament will be greater than the tension on themedial collateral ligament. In one embodiment, a drill guide can becoupled to distractor 1000 or the distal end of the femur 700. Drillguide holes are drilled into the distal end of the femur with the medialgap and the lateral gap equalized to support at least one bone cut forinstallation of a femoral prosthetic component. The load magnitudeapplied to the lateral plate 604 and the medial plate 606 can also beequalized. For example, soft tissue release can be used to reduce thetension of the lateral collateral ligament until the measured loadmagnitude on the lateral plate 604 equals the load magnitude on themedial plate 606. Thus, the installation of the femoral prostheticcomponent on the distal end of femur 700 results in the medialcompartment of the knee joint spaced equal to the lateral compartment(or a spacing chosen by the surgeon), equal load magnitudes applied ineach compartment (or a load distribution chosen by the surgeon), withthe leg in alignment to the mechanical axis. Note also that theequalization is performed in the leg in extension and flexion therebymaintaining the alignment and balance throughout the range of motion. Ingeneral, the measurement data generated during the use of distractor1000 should correspond to measurement data generated after installationof the final prosthetic components of the knee joint.

FIG. 51 depicts an exemplary diagrammatic representation of a machine inthe form of a system 4100 within which a set of instructions, whenexecuted, may cause the machine to perform any one or more of themethodologies discussed above. In some embodiments, the machine operatesas a standalone device. In some embodiments, the machine may beconnected (e.g., using a network) to other machines. In a networkeddeployment, the machine may operate in the capacity of a server or aclient user machine in server-client user network environment, or as apeer machine in a peer-to-peer (or distributed) network environment.

The machine may comprise a server computer, a client user computer, apersonal computer (PC), a tablet PC, a laptop computer, a desktopcomputer, a control system, logic circuitry, a sensor system, an ASIC,an integrated circuit, a network router, switch or bridge, or anymachine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. It will beunderstood that a device of the present disclosure includes broadly anyelectronic device that provides voice, video or data communication.Further, while a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein.

System 4100 may include a processor 4102 (e.g., a central processingunit (CPU), a graphics processing unit (GPU, or both), a main memory4104 and a static memory 4106, which communicate with each other via abus 4108. System 4100 may further include a video display unit 4110(e.g., a liquid crystal display (LCD), a flat panel, a solid statedisplay, or a cathode ray tube (CRT)). System 4100 may include an inputdevice 4112 (e.g., a keyboard), a cursor control device 4114 (e.g., amouse), a disk drive unit 4116, a signal generation device 4118 (e.g., aspeaker or remote control) and a network interface device 4120.

The disk drive unit 4116 can be other types of memory such as flashmemory and may include a machine-readable medium 4122 on which is storedone or more sets of instructions (e.g., software 4124) embodying any oneor more of the methodologies or functions described herein, includingthose methods illustrated above. Instructions 4124 may also reside,completely or at least partially, within the main memory 4104, thestatic memory 4106, and/or within the processor 4102 during executionthereof by the system 4100. Main memory 4104 and the processor 4102 alsomay constitute machine-readable media.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Applications that may include the apparatusand systems of various embodiments broadly include a variety ofelectronic and computer systems. Some embodiments implement functions intwo or more specific interconnected hardware modules or devices withrelated control and data signals communicated between and through themodules, or as portions of an application-specific integrated circuit.Thus, the example system is applicable to software, firmware, andhardware implementations.

In accordance with various embodiments of the present disclosure, themethods described herein are intended for operation as software programsrunning on a computer processor. Furthermore, software implementationscan include, but not limited to, distributed processing orcomponent/object distributed processing, parallel processing, or virtualmachine processing can also be constructed to implement the methodsdescribed herein.

The present disclosure contemplates a machine readable medium containinginstructions 4124, or that which receives and executes instructions 4124from a propagated signal so that a device connected to a networkenvironment 4126 can send or receive voice, video or data, and tocommunicate over the network 4126 using the instructions 4124. Theinstructions 4124 may further be transmitted or received over a network4126 via the network interface device 4120.

While the machine-readable medium 4122 is shown in an example embodimentto be a single medium, the term “machine-readable medium” should betaken to include a single medium or multiple media (e.g., a centralizedor distributed database, and/or associated caches and servers) thatstore the one or more sets of instructions. The term “machine-readablemedium” shall also be taken to include any medium that is capable ofstoring, encoding or carrying a set of instructions for execution by themachine and that cause the machine to perform any one or more of themethodologies of the present disclosure.

The term “machine-readable medium” shall accordingly be taken toinclude, but not be limited to: solid-state memories such as a memorycard or other package that houses one or more read-only (non-volatile)memories, random access memories, or other re-writable (volatile)memories; magneto-optical or optical medium such as a disk or tape; andcarrier wave signals such as a signal embodying computer instructions ina transmission medium; and/or a digital file attachment to e-mail orother self-contained information archive or set of archives isconsidered a distribution medium equivalent to a tangible storagemedium. Accordingly, the disclosure is considered to include any one ormore of a machine-readable medium or a distribution medium, as listedherein and including art-recognized equivalents and successor media, inwhich the software implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the disclosure is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are periodicallysuperseded by faster or more efficient equivalents having essentiallythe same functions. Accordingly, replacement standards and protocolshaving the same functions are considered equivalents.

FIG. 52 is an illustration of a communication network 4200 formeasurement and reporting in accordance with an exemplary embodiment.Briefly, the communication network 4200 expands broad data connectivityto other devices or services. As illustrated, the measurement andreporting system 4255 can be communicatively coupled to thecommunications network 4200 and any associated systems or services.

As one example, measurement system 4255 can share its parameters ofinterest (e.g., angles, load, balance, distance, alignment,displacement, movement, rotation, and acceleration) with remote servicesor providers, for instance, to analyze or report on surgical status oroutcome. This data can be shared for example with a service provider tomonitor progress or with plan administrators for surgical monitoringpurposes or efficacy studies. The communication network 4200 can furtherbe tied to an Electronic Medical Records (EMR) system to implementhealth information technology practices. In other embodiments, thecommunication network 4200 can be communicatively coupled to HISHospital Information System, HIT Hospital Information Technology and HIMHospital Information Management, EHR Electronic Health Record, CPOEComputerized Physician Order Entry, and CDSS Computerized DecisionSupport Systems. This provides the ability of different informationtechnology systems and software applications to communicate, to exchangedata accurately, effectively, and consistently, and to use the exchangeddata.

The communications network 4200 can provide wired or wirelessconnectivity over a Local Area Network (LAN) 4201, a Wireless Local AreaNetwork (WLAN) 4205, a Cellular Network 4214, and/or other radiofrequency (RF) system (see FIG. 4). The LAN 4201 and WLAN 4205 can becommunicatively coupled to the Internet 4220, for example, through acentral office. The central office can house common network switchingequipment for distributing telecommunication services. Telecommunicationservices can include traditional POTS (Plain Old Telephone Service) andbroadband services such as cable, HDTV, DSL, VoIP (Voice over InternetProtocol), IPTV (Internet Protocol Television), Internet services, andso on.

The communication network 4200 can utilize common computing andcommunications technologies to support circuit-switched and/orpacket-switched communications. Each of the standards for Internet 4220and other packet switched network transmission (e.g., TCP/IP, UDP/IP,HTML, HTTP, RTP, MMS, SMS) represent examples of the state of the art.Such standards are periodically superseded by faster or more efficientequivalents having essentially the same functions. Accordingly,replacement standards and protocols having the same functions areconsidered equivalent.

The cellular network 4214 can support voice and data services over anumber of access technologies such as GSM-GPRS, EDGE, CDMA, UMTS, WiMAX,2G, 3G, WAP, software defined radio (SDR), and other known technologies.The cellular network 4214 can be coupled to base receiver 4210 under afrequency-reuse plan for communicating with mobile devices 4202.

The base receiver 4210, in turn, can connect the mobile device 4202 tothe Internet 4220 over a packet switched link. The internet 4220 cansupport application services and service layers for distributing datafrom the measurement system 4255 to the mobile device 4202. Mobiledevice 4202 can also connect to other communication devices through theInternet 4220 using a wireless communication channel.

The mobile device 4202 can also connect to the Internet 4220 over theWLAN 4205. Wireless Local Access Networks (WLANs) provide wirelessaccess within a local geographical area. WLANs are typically composed ofa cluster of Access Points (APs) 4204 also known as base stations. Themeasurement system 4255 can communicate with other WLAN stations such aslaptop 4203 within the base station area. In typical WLANimplementations, the physical layer uses a variety of technologies suchas 802.11b or 802.11g WLAN technologies. The physical layer may useinfrared, frequency hopping spread spectrum in the 2.4 GHz Band, directsequence spread spectrum in the 2.4 GHz Band, or other accesstechnologies, for example, in the 5.8 GHz ISM band or higher ISM bands(e.g., 24 GHz, etcetera).

By way of the communication network 4200, the measurement system 4255can establish connections with a remote server 4230 on the network andwith other mobile devices for exchanging data. The remote server 4230can have access to a database 4240 that is stored locally or remotelyand which can contain application specific data. The remote server 4230can also host application services 4250 directly, or over the internet4220.

In general, a robot can support or assist the distraction of a kneejoint in under control of a surgeon. The distractor 10 or distractor1000 disclosed herein above can be coupled to the robot. One example ofthe robot is the Robodoc surgical robot with a robotic assisted TKAapplication. A robot can also include surgical CNC robots, surgicalhaptic robots, surgical teleoperative robots, surgical hand-held robots,or any other surgical robot. Distractor 10 can be automated to couple toand work with the robot thereby replacing direct hand control by thesurgeon. The actions taken by the robot in control of distractor 10 canbe smoother and more accurate by having the robot use the measurementdata in real-time and providing feedback to distractor 10 for subsequentsteps. An added benefit can be shortening the time of surgery thatreduces the time a patient is under anesthesia.

The robot can be configured to perform computer-assisted surgery andmore specifically knee surgery with distractor 10. Typically, the robotand distractor 10 is used for computer-assisted surgery to improveperformance, reduce time, and minimize variation in the distraction,alignment, bone cuts, and installation of one or more prostheticcomponents for a prosthetic knee joint. The robot can controldistraction, medial-lateral tilt, loading, tissue release, braking, anddrilling guide holes using the real-time measurement data sent fromdistractor 10.

In general, measurement data from distractor 10 can be wirelesslytransmitted to a computer of the robot. Alternatively, the measurementdata can be hard wired to the robot. Examples of measurement data fromdistractor 10 can be position data, distraction distance, load,medial-lateral tilt, or other data relevant to a prosthetic kneeinstallation. The measurement data received by the robot can be furtherprocessed to calculate and display measurement data needed by thesurgeon for the distraction and preparation of the bone surfaces of theknee joint. The prepared bone surfaces will receive a prostheticcomponent that supports alignment to the mechanical axis of the leg. Inone embodiment, the computer includes one or more algorithms that areused at various stages of the surgery. The measurement data is input tothe algorithms of the robot and the algorithms can convert the data intoinformation displayed on the display for robotic actions that are usedto make bone cuts, pin placements, prosthetic component sizing, etc. . .. or provide feedback on actions that the surgeon may take. The feedbackmay take the form of audible, visual, or haptic feedback that guides thesurgeon on the distraction or subsequent steps taken by the robot tosupport or resist an action based on the measurement data. The feedbackcan also smooth or prevent motions by a user that could be detrimentalto the surgery. Furthermore, the status of the measurement data can beused to generate a workflow that is subsequently implemented by asurgeon or automatically by the robot to enhance performance andreliability of the knee joint installation.

FIG. 53 illustrates a surgical apparatus 5000 having three distractingmechanisms configured to distract a knee joint in accordance with anexample embodiment. In general, surgical apparatus 5000 and surgicalapparatus 6000 disclosed herein below in FIG. 64 is configured for usein the musculoskeletal system to generate quantitative measurement datausing one or more sensors. In one embodiment, surgical apparatus 5000and surgical apparatus 6000 is adapted for use for providing a kineticassessment having quantitative measurement data for the musculoskeletalsystem, knee, hip, shoulder, spine, ankle, wrist, hand, foot, or bone.In one embodiment, surgical apparatus 5000 and 6000 is configured tosupport installation of a prosthetic joint of the musculoskeletalsystem. Surgical apparatus 5000 and 6000 can include, but are notlimited to measurement of parameters such as height, length, width,tilt/slope, position, orientation, alignment, offset, rotation, tension,load magnitude, force, pressure, contact point location, displacement,density, viscosity, pH, light, color, sound, optical, vascular flow,visual recognition, humidity, alignment, rotation, inertial sensing,turbidity, bone density, fluid viscosity, strain, angular deformity,vibration, torque, elasticity, motion, and temperature. Electroniccircuitry 150 as disclosed herein in FIG. 15 can be coupled to surgicalapparatus 5000 to control a measurement process and transmit measurementdata. For example, electronic circuitry 150 of FIG. 15 can be coupled orhoused on or in surgical apparatus 5000 to couple to one or more sensorsfor measuring a parameter and transmitting quantitative measurementdata. A computer 5026 with a display is configured to receive andprovide the quantitative measurement data. For example, Hall Effectsensor 204 or linear Hall sensor 222 of FIGS. 16-20 can be configured tomeasure femoral support tilt or compartment height on surgical apparatus5000 as disclosed herein above. Surgical apparatus 5000 can furthercomprise a measurement module having at least one sensor. Themeasurement module includes at least one sensor configured to measure aparameter. In one embodiment, the measurement module is removable fromsurgical apparatus 5000 and can be used as a trialing device laterduring the surgical procedure. The measurement module generatesquantitative measurement data and transmits the measurement data to thecomputer for display. The computer can include a GUI and convert thequantitative measurement data into visual, audible, or haptic forms thatsupports the rapid assimilation of the data to reduce surgical time. Forexample, quantitative measurement data from surgical apparatus 5000 orthe measurement module received by computer 5026 and displayed ondisplay 5028 can be presented as shown in FIG. 28, FIG. 30, FIG. 33,FIG. 37, and FIG. 38 as disclosed herein above. The computer can furtherprovide workflows based on the quantitative measurement data thatresults in at least one adjustment or change that optimizes theinstallation.

In general, surgical apparatus 5000 comprises a first distractionmechanism, a second distraction mechanism, and a third distractionmechanism. Surgical apparatus 5000 is configured to separate portions ofthe musculoskeletal system in a predetermined manner and generatequantitative measurement data. In one embodiment, surgical apparatus5000 is configured to be inserted between a first bone and a second boneof the musculoskeletal system. The first or second bones can be natural,prepared, or have a prosthetic component coupled to it. The insertedportion of surgical apparatus 5000 distracts a first side and a secondside of the musculoskeletal system. The first distraction mechanism ofsurgical apparatus 5000 is configured to increase or decrease a heighton the first side and the second side simultaneously by an equal amount.The second distraction mechanism is configured to increase or decrease aheight on the first side. The third distraction mechanism is configuredto increase or decrease a height on the second side. The first, second,and third distraction mechanisms can be operated by the hand of the useror controlled by a robot. Although surgical apparatus 5000 is shownadjusting the height on a first side and a second side of themusculoskeletal system, surgical apparatus 5000 can have more than twoareas that are distracted in combination or independently distracted. Inone embodiment, surgical apparatus 5000 is configured to providequantitative measurement data that supports at least one bone cut on ajoint. A tilt is generated by independently changing a height on a firstside or the second side. The tilt or heights of the first and secondsides is measured and provided to a computer in viewing distance fromthe surgery. In one embodiment, surgical apparatus 5000 is configured tosupport alignment, adjust load magnitude, and load balance between thefirst side and the second side prior to installation of a prostheticcomponent. The at least one bone cut supported by the surgical apparatus5000 incorporates alignment, load magnitudes and balance to theprosthetic component installation using quantitative measurement datathereby eliminating modification to the musculoskeletal system orprosthetic components after installation of the prosthetic components.The description of surgical apparatus 5000 also applies to surgicalapparatus 6000 shown in FIG. 64.

In one embodiment, surgical apparatus 5000 is used to supportinstallation of a prosthetic component or a prosthetic joint. In oneembodiment, surgical apparatus 5000 is configured to support one or morebone cuts that support improved alignment, optimal loading, position ofload, or load balance. Components of surgical apparatus 5000 cancomprise plastic, metal, structural fibers, metal alloys, or otherstructural materials. In one embodiment, stainless steel is used forstructural components. Surgical apparatus 5000 can be a disposablesurgical tool. Alternatively, surgical apparatus 5000 can be a reusabletool that is sterilized between each use. In the example, surgicalapparatus 5000 is illustrated for use in a knee joint. Surgicalapparatus 5000 is shown placed in a knee joint with a leg in flexion. Atibial support 5006 and a femoral support 5008 couples to surgicalapparatus 5000. Tibial support 5006 couples to tibia 5004. Femoralsupport 5008 couples to femur 5002. A medial compartment and a lateralcompartment of the knee joint can be distracted independently or byequal amounts by surgical apparatus 5000. A module 5024 couples tofemoral support 5008. Module 5024 includes one or more sensors tomeasure at least one parameter. In one embodiment, module 5024 includesforce, pressure, or load sensors configured to measure loading appliedto the medial compartment or the lateral compartment of the knee joint.The one or more sensors are operatively coupled to electronic circuitryin module 5024. The electronic circuitry is configured to control ameasurement process and to transmit measurement data. The measurementdata from the one or more sensors can be transmitted to a computer 5026for further processing and to be displayed on a display 5028. In oneembodiment, surgical apparatus 5000 is configured to measure parameterssuch compartment height, medial-lateral tilt, load, alignment, orbalance where the sensor output can be viewed on display 5028 coupled tocomputer 5026. In one embodiment, display 5028 can have a graphical userinterface that supports graphical data implemented to support rapidassimilation of measurement data from surgical apparatus 5000 to reducesurgical time while installing one or more prosthetic components usingquantitative measurement data. Alternatively, gauges 5016 can be coupledto surgical apparatus 5000. In one embodiment, gauges 5016 can bemechanical gauges that couple to the three distracting mechanisms tomechanically measure and display the compartment heights (medial,lateral, or both), balance, alignment, load, or the medial-lateralheight.

Surgical apparatus 5000 is configured to measure, distract, align,balance, tilt, and support bone cuts in a joint of the musculoskeletalsystem prior to installation of a prosthetic component. In the example,surgical apparatus 5000 is adapted for use to support a total kneearthroplasty. As mentioned previously, surgical apparatus 5000 can beused for the musculoskeletal system, bone, spine, knee, shoulder, hip,ankle, elbow, wrist, hand, foot, and other areas where quantitativemeasurement is useful. Surgical apparatus 5000 can be used to set oradjust the height of the medial compartment, the height of the lateralcompartment, or both knee compartments by adjustment of tibial support5006 and femoral support 5008 under user control. In one embodiment, apredetermined flow is established using surgical apparatus 5000 thatreduces alignment error of the knee joint by one or more corrective bonecuts that support installation of a tibial prosthetic component or afemoral prosthetic component to correct for the misalignment.

Tibial support 5006 of surgical apparatus 5000 couples to a proximal endof tibia 5004. In the example, tibial support 5006 couples to a preparedbone surface of tibia 5004. In one embodiment, the prepared bone surfaceat the proximal end of tibia 5004 is cut relative to the mechanical axisof the leg as a reference surface. Surgical apparatus 5000 comprises adistraction mechanism 5010, a distraction mechanism 5012, and adistraction mechanism 5014 where each can change a distraction height ofat least one compartment on the knee joint. Tibial support 5006 couplesto the distraction mechanism 5010. Distraction mechanism 5010 isconfigured to move tibial support 5006 relative to femoral support 5008.In one embodiment, distraction mechanism 5010 simultaneously distractsthe medial compartment and the lateral compartment of a knee joint by anequal distance or an equal amount. In one embodiment, distractionmechanism 5012 and distraction mechanism 5014 work together orseparately as a tilt mechanism. The tilt mechanism changes the medialcompartment height relative to the lateral compartment height. Ingeneral, the tilt mechanism changes the position of a first supportstructure such as femoral support 5008 relative to a second supportstructure such as tibial support 5006 of a tensor such as surgicalapparatus 5000.

Femoral support 5008 of surgical apparatus 5000 couples to a distal endof femur 5002. Module 5024 has a medial surface and a lateral surfaceconfigured to respectively couple to a medial condyle 5020 and a lateralcondyle 5022 of femur 5002. In one embodiment, surgical apparatus 5000couples to a natural femur (before bone cuts for a femoral prostheticcomponent) and surgical apparatus 5000 supports movement of femur 5002relative to tibia 5004. Medial condyle 5020 and lateral condyle 5022respectively couple to and rotate on the medial surface and the lateralsurface of module 5024. Alternatively, the medial condyle and thelateral condyle can be femoral prosthetic component coupled to femur5002. The position and the movement of the leg can be monitored by aposition sensor in module 5024. For example, a gyroscope, accelerometer,or other position tracking device can be used to report leg or kneejoint position. Femoral support 5008 couples to distraction mechanism5012 and distraction mechanism 5014. Distraction mechanism 5012 changesa height of the medial compartment of the knee joint. Distractionmechanism 5012 is configured to move femoral support 5008 to raise orlower a height of the medial compartment of the knee joint. Distractionmechanism 5014 changes a height of the medial compartment of the kneejoint. Similarly, distraction mechanism 5014 is configured to movefemoral support 5008 to raise or lower a height of the lateralcompartment of the knee joint. In one embodiment, distraction mechanisms5012 and 5014 each comprise a screw that can rotated to respectivelychange the height of the medial compartment and the height of thelateral compartment such that the position of femoral support 5008 movesrelative to tibial support 5006 and changes the medial-lateral tilt ofthe femoral support 5008.

In general, surgical apparatus 5000 is configured to distract a jointregion to support one or more bone cuts that support installation of oneor more prosthetic components. In the example, the bone cuts supportplacement of a tibial prosthetic component on the proximal end of tibia5004, a femoral prosthetic component on the distal end of femur 5002,and an insert there between. The insert is retained by the tibialprosthetic component and provides a medial articular surface and alateral articular surface that respectively couples to the medialcondyle and the lateral condyle of the femoral prosthetic component tosupport leg movement. In one embodiment, surgical apparatus 5000supports measuring or checking alignment of femur 5002 relative to tibia5004 in a kinetic assessment where the joint is loaded similar to afinal prosthetic installation. In one embodiment, surgical apparatus5000 is offset, more specifically, tibial support 5006 and femoralsupport 5006 are offset to allow loading of the knee joint with apatella or extensor mechanism anatomically positioned under distractionwith full rotation of the knee joint. Surgical apparatus 5000 furthersupports at least one bone cut for installing a prosthetic component. Inone embodiment, the at least one bone cut supports balanced loading orsetting the medial compartment or the lateral compartment respectivelyto a predetermined medial loading and a predetermined lateral loading.Furthermore, the loading in each compartment can be measured over arange of motion of the leg to determine if the loading in eachcompartment stays within a predetermined load range over a range ofmotion of the knee joint. Further correction can be made in real-time toadjust the loading in each compartment. A bone cutting jig can couple tosurgical apparatus 5000 or a bone cutting jig can be positioned bysurgical apparatus 500 to support at least one bone cut that installs aprosthetic component to reduce alignment error or improve balance.Surgical apparatus 5000 further can monitor or support change of theposition of contact points to the medial and lateral compartment and theabsolute loading at the contact points on the medial and lateralcompartment over the range of motion.

Module 5024 transmits measurement data to computer 5026. Information isdisplayed on display 5028. Display 5028 displays the measurement datathat allows a user to obtain information at a glance during an operationin a surgical environment. Computer 5026 is typically placed outside thesurgical field of an operating room but in a location where it caneasily be seen by a surgical team. In one embodiment, a module portion5030 corresponding to module 5024 is displayed on display 5028. In oneembodiment, module portion 5030 includes the medial (M) and lateral (L)articular surfaces. Medial loading 5038 and lateral loading 5040 aremeasured loadings on the medial articular surface and the lateralarticular surface of module 5024 and displayed on module portion 5030 ondisplay 5028. In one embodiment, medial loading 5038 and lateral loading5040 correspond to a height of the medial compartment and a height ofthe lateral compartment as distracted by surgical apparatus 5000. Themedial compartment height and the lateral compartment height can bemeasured by surgical apparatus 5000 and displayed on display 5028. Anarea 5046 and an area 5048 can also be displayed respectively on themedial articular surface and the lateral articular surface of moduleportion 5030 on display 5028. In the example, area 5046 and area 5048are triangular in shape. Area 5046 and 5048 can differ in shape andsize. In general, area 5046 and area 5048 respectively define a regionof contact of medial condyle 5020 and lateral condyle 5022 to ensurereliability and performance of the knee joint over a range of motion. Ingeneral, the contact points should not go outside area 5046 or area 5048over the range of motion of the knee joint. In one embodiment, anadjustment or modification may have to be performed to correct movementof the contact points outside area 5046 or area 5048. In one embodiment,computer 5026 can provide a workflow of one or more adjustments that canbe performed with real-time feedback on display 5028 that brings thecontact points within area 5046 and 5048. Contact points 5034 and 5036on display 5028 respectively correspond to a contact point of medialcondyle 5020 and a contact point of lateral condyle 5022 coupling to themedial articular surface and the lateral articular surface of module5024. As mentioned contact points 5034 and 5036 will move in real-timefrom transmitted measurement data as the position of the leg is changedor moved over the range of motion.

One adjustment to keep contact points 5034 and 5036 within areas 5046and 5048 over the range of motion is to change the position of thetibial support 5006 on the prepared surface of tibia 5004. Rotatingtibial support 5006 on the prepared surface of tibia 5004 can repositionthe contact points 5034 and 5036. The leg can be rotated over a range ofmotion and contact points 5034 and 5036 can be monitored in real-time.Alternatively, areas 5046 or 5048 can be highlighted or indicate whencontact points 5034 and 5036 are near or outside the boundary of areas5046 and 5048. The amount of contact point rotation 5032 of tibialsupport 5006 can be measured by a sensor in module 5024 and displayed ondisplay 5028 in a display box 5032 on display 5028. In one embodiment,the tibial prosthetic component would also be installed having thisrotation after removal of surgical apparatus 5000.

In one embodiment, measurement data is transmitted wirelessly. A signalstrength meter 5044 of the transmission from the module to computer 5026is shown on display 5028. In one embodiment, module 5024 has an internalpower source. For example, module 5024 can include one or more batteriesto power the electronic circuitry. In one embodiment, module 5024 is adisposable surgical apparatus as the batteries in module 5024 areconfigured to last a single operation. In one embodiment, opening module5024 cannot be opened to replace the batteries without damage. Batterysymbol indicates the remaining power within module 5024 and is shown ondisplay 5028. The leg or knee joint position in flexion or extension isindicated by in area 5050 of display 5028. Similarly, measured alignmentof the leg is indicated in area 5052 of display 5028.

Tibial support 5006 and femoral support 5008 are provided with surgicalapparatus 5000 in more than one size. In one embodiment, tibial support5006 and femoral support 5008 are provided in small, medium, and largesizes that can be used for a majority of the population. In oneembodiment, femoral support 5008 couples through a first pivot point anda second pivot point respectively to distraction mechanism 5012 anddistraction mechanism 5014. Loading on femoral support 5008 isdistributed between the first and second pivot points to surgicalapparatus 5000. The first and second pivot points are configured to tiltfemoral support 5008 when the height of the medial compartment differsfrom the height of the lateral compartment. The tibial support 5006 isretained to distraction mechanism using clips 5018. Clips 5018 canfurther include one or more magnets that align and retain tibial support5006 or clips 5018 to surgical apparatus 5000.

FIG. 54 is an exploded view of surgical apparatus 5000 in accordancewith an example embodiment. In general, a left knee distractor isprovided for a left knee joint and a right knee distractor is providedfor a right knee joint. The right and left knee distractors each have anoffset toward the medial side. The patella is reflected laterally duringdistraction or tensor insertion, once inserted the patella is able torest over the center of the knee joint because of the medial offsetplaced in the right or left knee distractor. This allows the patella toload the knee joint through a range of motion with the right or leftknee distractor in place. In the example, surgical apparatus 5000 isconfigured for distracting the left knee joint. In other words, themedial offset of surgical apparatus 5000 is on the medial side for aleft leg. Surgical apparatus 5000 for the left knee cannot be used onthe right knee. Similarly, if surgical apparatus 5000 has an offset fora right knee, it cannot be used for a left knee. The right kneedistractor is not shown, as the components and operation are the sameexcept for the offset.

Distraction mechanism 5010, distraction mechanism 5012, and distractionmechanism 5014 of surgical apparatus 5000 is supported and aligned by acage system 5011. Cage system 5011 comprises a cap 5062, an anteriormedial guide shaft 5064, an anterior lateral guide shaft 5066, aposterior medial guide shaft 5068, a posterior lateral guide shaft 5070,and a base 5060. In one embodiment, anterior medial guide shaft 5064,anterior lateral guide shaft 5066, posterior medial guide shaft 5068,and posterior lateral guide shaft 5070 couple between base 5060 and cap5062. In one embodiment, anterior medial guide shaft 5064, anteriorlateral guide shaft 5064, posterior medial guide shaft 5068, andposterior lateral guide shaft 5070 couple between base 5060 and cap 5062in a square or rectangular pattern to support movement of distractionmechanism 5010, distraction mechanism 5012, and distraction mechanism5014.

A distal end of anterior medial guide shaft 5064 couples to a medialanterior opening in base 5060. Screw 5072 couples through the medialanterior opening in base 5060 coupling the distal end of anterior medialguide shaft 5064 to base 5060. Similarly, a proximal end of anteriormedial guide shaft 5064 couples to a medial anterior opening in cap5062. Screw 5080 couples through the medial anterior opening in cap 5062coupling the proximal end of anterior medial guide shaft 5064 to cap5062. In one embodiment, the proximal and distal ends of anterior medialguide shaft 5064 have threaded openings configured to respectivelyreceive screws 5080 and 5072. In one embodiment, a portion of theproximal and distal ends of anterior medial guide shaft 5064 can have areduced diameter to fit within the first openings in base 5060 and cap5062 to support alignment.

A distal end of anterior lateral guide shaft 5066 couples to a lateralanterior opening in base 5060. Screw 5074 couples through the lateralanterior opening in base 5060 coupling the distal end of anteriorlateral guide shaft 5066 to base 5060. Similarly, a proximal end ofanterior lateral guide shaft 5066 couples to a lateral anterior openingin cap 5062. Screw 5082 couples through the lateral anterior opening incap 5062 coupling the proximal end of anterior lateral guide shaft 5066to cap 5062. In one embodiment, the proximal and distal ends of anteriorlateral guide shaft 5066 have threaded openings configured torespectively receive screws 5082 and 5074. In one embodiment, a portionof the proximal and distal ends of anterior lateral guide shaft 5066 canhave a reduced diameter to fit within the second openings in base 5060and cap 5062 to support alignment.

A distal end of posterior medial guide shaft 5068 couples to a medialposterior opening in base 5060. Screw 5076 couples through the medialposterior opening in base 5060 coupling the distal end of posteriormedial guide shaft 5068 to base 5060. Similarly, a proximal end ofposterior medial guide shaft 5068 couples to a medial posterior openingin cap 5062. Screw 5084 couples through the medial posterior opening incap 5062 coupling the proximal end of posterior medial guide shaft 5068to cap 5062. In one embodiment, the proximal and distal ends ofposterior medial guide shaft 5068 have threaded openings configured torespectively receive screws 5084 and 5076. In one embodiment, a portionof the proximal and distal ends of posterior medial guide shaft 5068 canhave a reduced diameter to fit within the third openings in base 5060and cap 5062 to support alignment.

A distal end of posterior lateral guide shaft 5070 couples to a lateralposterior opening in base 5060. Screw 5078 couples through the lateralposterior opening in base 5060 coupling the distal end of posteriorlateral guide shaft 5070 to base 5060. Similarly, a proximal end ofposterior lateral guide shaft 5070 couples to a lateral posterioropening in cap 5062. Screw 5086 couples through the lateral posterioropening in cap 5062 coupling the proximal end of posterior lateral guideshaft 5070 to cap 5062. In one embodiment, the proximal and distal endsof posterior lateral guide shaft 5070 can have threaded openingsconfigured to respectively receive screws 5086 and 5078. In oneembodiment, a portion of the proximal and distal ends of anteriorlateral guide shaft 5066 can have a reduced diameter to fit within thefourth openings in base 5060 and cap 5062 to support alignment. In oneembodiment, anterior medial guide shaft 5064, anterior lateral guideshaft 5066, posterior medial guide shaft 5068, and posterior lateralguide shaft 5070 are parallel to one another. In general, cap 5062, base5060, anterior medial guide shaft 5064, anterior lateral guide shaft5066, posterior medial guide shaft 5068, and posterior lateral guideshaft 5068 are configured to support movement and trajectory of thethree distraction mechanisms that comprise surgical apparatus 5000.

Distraction mechanism 5010 comprises tibial support holder 5088, cagesystem 5011, distraction lead screw 5092, and handle 5094. Distractionmechanism 5010 is configured to move tibial support 5006 relative tofemoral support 5008. In one embodiment, tibial support 5006 couples toa prepared bone surface of a proximal end of a tibia. In one embodiment,distraction mechanism 5010 simultaneously distracts a medial compartmentand a lateral compartment of a knee joint by equal amounts. Tibialsupport holder 5088 comprises a structure having a medial opening and alateral opening. Anterior medial guide shaft 5064 and anterior lateralguide shaft 5066 respectively couple through the medial opening and thelateral opening of tibial support holder 5088. Distraction lead screw5092 is configured to move tibial support holder 5088 under usercontrol. Distraction lead screw 5092 couples through an opening in base5060 to couple to threaded structure 5090 of tibial support structure5088. Threaded structure 5090 has a threaded opening configured toreceive distraction lead screw 5092. Distraction lead screw 5092 couplesthru the threaded opening of threaded structure 5090 to motivate tibialsupport holder 5088 when rotated. In one embodiment, the opening in base5060 for receiving distraction lead screw 5092 can be centrally locatedin base 5060. The surface in the opening in base 5060 can act as abearing surface to support alignment and rotation of distraction leadscrew 5092. In one embodiment, distraction lead screw 5092 can benon-threaded in a portion of distraction lead screw 5092 that couples tothe bearing surface in the opening of base 5060. Handle 5094 couples tothe distal end of distraction lead screw 5092. Rotating handle 5094engages distraction lead screw 5092 to threads within threaded structure5090 of tibial support holder 5088 to move tibial support holder 5088along a trajectory defined by anterior medial guide shaft 5064 andanterior lateral guide shaft 5066. Tibial support holder 5088 can movetowards or away from base 5060 depending on the direction of rotation ofdistraction lead screw 5092.

Tibial support 5006 couples to tibial support holder 5088. In oneembodiment, tibial support 5006 comprises a U-shaped structure 5152,beam structure 5148, and arms 5150. U-shaped structure 5152 isconfigured to couple to a bone or bone surface. In the example, U-shapedstructure 5152 has a bottom surface 5142 configured to couple to aprepared bone surface at the proximal end of a tibia and sidewalls 5146.The bottom surface 5142 couples to the bone or bone surface. Femoralsupport 5008 is configured to fit within U-shaped structure 5152 therebyminimizing a height during initial insertion in the knee joint. A beamstructure 5148 couples U-shaped structure 5152 to arms 5150. Beamstructure 5148 locates U-shaped structure 5152 at a predeterminedposition. In one embodiment, beam structure 5148 has a medial offset tosupport placement of the patella onto the knee joint after surgicalapparatus 5000 is inserted such that all measurements include patellarloading. In one embodiment, U-shaped structure 5152, beam structure5148, and arms 5150 are rigid and do not flex when distracting a jointof the musculoskeletal system. U-shaped structure 5142, beam structure5148, and arms 5150 can be formed as a single structure from one or morematerials such as metal, metal alloys, plastics, or composite materials.

Arms 5150 are configured to couple tibial support 5006 to tibial supportholder 5088. In one embodiment, tibial support holder 5088 has supportstructures 5100 having surfaces configured to couple to arms 5150 on amedial side and a lateral side of tibial support holder 5088. Tips 5098,cavities 5096, and retaining clip 5018 are configured to retain tibialsupport 5006 to tibial support holder 5088. A first arm of arms 5150couples to support structure 5100 on the medial side of tibial supportholder 5088. A second arm of arms 5150 couples to support structure 5100on the lateral side of tibial support holder 5088. A medial side and alateral side retaining clip 5100 of support structure 5100 respectivelycouples to a medial side and a lateral side cavity 5096 on arms 5150.Tibial support 5006 further includes a structure 5102 that is receivedby an opening 5104 in tibial support holder 5088. Structure 5102 couplesto tibial support holder 5088 in a manner that loading applied to tibialsupport 5006 is distributed to major structural surfaces of tibialsupport holder 5088. Structure 5102 and the surface in opening 5104 oftibial support holder 5088 are designed to distribute loads seen bysurgical apparatus 5000. In one embodiment, retaining clips 5018 arespring loaded and couple to the medial or lateral sides of tibialsupport holder 5088. In one embodiment, pressing retaining clip 5018allows room for arms 5150 to clear retaining clips 5018 during acoupling process. Releasing retaining clip 5018 places a portion ofretaining clip 5018 into cavity 5096 to prevent movement. In oneembodiment, retaining clips 5018 are shaped to fit within cavities 5096to lock and hold arms 5150 to tibial support holder 5088. Thus,retaining clip 5018 locks tibial support 5006 to tibial support holder5088. In one embodiment, tibial support 5006 has a retaining structure5098 that extends past support structures 5100. Retaining structure 5098couples to a posterior surface of support structures 5100 on the medialand lateral sides. Retaining structure 5098 prevents movement of arms5150 and retains tibial support 5006 to tibial support holder 5088 whenretaining clips 5018 are engaged with cavities 5096. In one embodiment,tibial support 5006 cannot be removed from tibial support holder 5088unless retaining clips 5018 are freed from cavities 5096 and retainingstructure 5098 is lifted above support structure 5100 such that tibialsupport 5006 can be freely pulled away from tibial support holder 5088.In one embodiment, portions of tibial support holder 5088 or tibialsupport 5006 can include magnets. For example, cavities 5096 orretaining clip 5018 can include one or magnets that support retention ofthe portion of retaining clip 5018 to cavities 5096 that hold tibialsupport 5006 to tibial support holder 5006.

Distraction mechanism 5012 comprises a medial support structure 5106,cage system 5011, and a medial tilting screw 5110. Medial supportstructure 5106 includes a first opening, a second opening, and athreaded opening. Distraction mechanism 5012 is configured to movemedial support structure 5106 relative to tibial support 5006. Femoralsupport 5008 is configured to couple to medial support structure 5106.Raising or lowering medial support structure 5106 changes a height ofthe medial compartment of the knee joint. In one embodiment, a directionof movement of medial support structure 5106 is determined by cagesystem 5011. Anterior medial guide shaft 5064 couples through the firstopening in medial support structure 5106. Similarly, posterior medialguide shaft 5068 couples through the second opening in medial supportstructure 5106. Movement and trajectory of medial support structure 5106are aligned to anterior medial guide shaft 5064 and posterior medialguide shaft 5068. The surfaces within the first and second openings ofmedial support structure 5106 can be bearing surfaces to reduce frictionas medial support structure 5106 moves up or down within cage system5011. Medial tilting screw 5110 couples through an opening in cap 5062and the head of medial tilting screw 5110 is supported by cap 5062. Inone embodiment, the opening in cap 5062 is between openings for anteriormedial guide shaft 5064 and posterior medial guide shaft 5068 in cap5062. Medial tilting screw 5110 couples through the opening into thethreaded opening of medial support structure 5106. In one embodiment,medial tilting screw 5110 couples to the threaded opening of medialsupport structure 5106 parallel to anterior medial guide shaft 5064 orposterior medial guide shaft 5068. In one embodiment, the threads ofmedial tilting screw 5110 engage with the threads in the threadedopening of medial support structure 5106 to hold medial supportstructure 5106 in a fixed position. The engaged threads between medialtilting screw 5110 and the threaded opening in medial support structure5106 can support loading applied to femoral support 5008 and will notchange the medial compartment height unless medial tilting screw 5110 isrotated. The opening in cap 5062 for receiving medial tilting screw 5110can be threaded or non-threaded. In one embodiment, medial tilting screw5110 is an Allen head screw. An Allen wrench can be used to rotatemedial tilting screw 5110. Rotating medial tilting screw 5110 can pullmedial support structure 5106 towards cap 5062 or away from cap 5062depending on the direction of rotation.

Distraction mechanism 5014 comprises a lateral support structure 5108,cage system 5011 and a lateral tilting screw 5112. Medial supportstructure 5108 includes a first opening, a second opening, and athreaded opening. Distraction mechanism 5014 is configured to movelateral support structure 5108 relative to tibial support 5006. Femoralsupport 5008 is configured to couple to lateral support structure 5108.Raising or lowering lateral support structure 5108 changes a height ofthe lateral compartment of the knee joint. In one embodiment, adirection of movement of medial support structure 5108 is determined bycage system 5011. Anterior lateral guide shaft 5066 couples through thefirst opening in lateral support structure 5108. Similarly, posteriorlateral guide shaft 5070 couples through the second opening in lateralsupport structure 5108. Movement and trajectory of lateral supportstructure 5108 are aligned to anterior lateral guide shaft 5066 andposterior lateral guide shaft 5070. The surfaces within the first andsecond openings of medial support structure 5108 can be bearing surfacesto reduce friction as lateral support structure 5108 moves up or downwithin cage system 5011. Lateral tilting screw 5112 couples through anopening in cap 5062 and the head of lateral tilting screw 5112 issupported by cap 5062. In one embodiment, the opening in cap 5062 isbetween openings for anterior lateral guide shaft 5066 and posteriorlateral guide shaft 5070 in cap 5062. Lateral tilting screw 5112 couplesthrough the opening in cap 5062 into the threaded opening of lateralsupport structure 5108. In one embodiment, lateral tilting screw 5112couples to the threaded opening of lateral support structure 5106parallel to anterior lateral guide shaft 5066 or posterior lateral guideshaft 5070. In one embodiment, the threads of lateral tilting screw 5112engage with the threads in the threaded opening of lateral supportstructure 5108 to hold lateral support structure 5108 in a fixedposition. The engaged threads between lateral tilting screw 5112 and thethreaded opening in lateral support structure 5108 can support loadingapplied to femoral support 5008 and will not change the lateralcompartment height unless lateral tilting screw 5112 is rotated. Theopening in cap 5062 for receiving lateral tilting screw 5112 can bethreaded or non-threaded. In one embodiment, lateral tilting screw 5112is an Allen head screw. An Allen wrench can be used to rotate lateraltilting screw 5112. Rotating lateral tilting screw 5112 can pull lateralsupport structure 5108 towards cap 5062 or away from cap 5062 dependingon the direction of rotation.

Distraction mechanisms 5010, 5012, and 5014 can be motivated by meansother than screws or non-manually as disclosed herein above. Forexample, movement of distraction mechanism 5010, 5012, or 5014 can becontrolled pneumatically or by actuators. The process can also beautomated to precisely turn distraction mechanisms 5010, 5012, or 5014via a control system using feedback from sensors on surgical apparatus5000 or module 5024. Thus, distraction mechanism 5010, 5012, and 5014are adaptable for use in robotic surgery or can be used manually undersurgeon control. The implementation of distraction mechanism 5010, 5012,and 5014 with cage system 5011 supports higher loading at lower weightthan other designs.

In one embodiment, a spacer 5140 is used to place medial supportstructure 5106 and lateral support structure 5108 in a referenceposition. Spacer 5140 has a predetermined height that determines thereference position. Spacer 5140 has a first opening and a second openingthat respectively couples through posterior medial guide shaft 5068 andposterior lateral guide shaft 5070 of cage system 5011. Spacer 5140couples between base 5060 and medial support structure 5106. Similarly,spacer 5140 couples between base 5060 and lateral support structure5108. In one embodiment, the reference position is established whensurgical apparatus 5000 is in a minimum height position. In oneembodiment, the minimum height position corresponds to a minimum heightof surgical apparatus 5000 measured from a bottom surface 5142 of tibialsupport 5006 to exposed surfaces of covers 5126 and 5128 that couple tomodule 5024. Module 5024 is placed on and retained by femoral support5008. A first side of spacer 5140 will couple to base 5060 and secondside of spacer 5140 will couple to medial support structure 5106 andlateral support structure 5108. In one embodiment, the minimum height ofsurgical apparatus 5000 corresponds to a bottom surface 5170 of femoralsupport 5008 being co-planar with bottom surface 5142 of tibial support5006. In one embodiment, the position of spacer 5140 can be fixed suchthat spacer 5140 remains coupled to base 5060 when medial or lateralcompartment heights are changed.

Femoral support 5008 is configured to couple to a femur of a knee joint.In one embodiment, femoral support 5008 couples to a medial condyle anda lateral condyle at a distal end of the femur. A module 5024 couplesbetween the condyles of the femur and femoral support 5008. In oneembodiment, cover 5126 and cover 5128 respectively overlie a medial side5130 and a lateral side 5132 of module 5024. In one embodiment, covers5126 and 5128 are rigid and do not flex. Module 5024 includes at leastone sensor to measure a parameter, a power source, and electroniccircuitry to control a measurement process and transmit measurement datato a computer. In one embodiment, surgical apparatus 5000 is in asurgical field of an operating room and the computer is placed in theoperating room where the surgeon or surgical team can view theinformation generated by module 5024 and surgical apparatus 5000. In oneembodiment, measurement data from module 5024 and surgical apparatus5000 can be used to calculate alignment, leg position, measure medialcompartment loading, measure lateral compartment loading, identify amedial condyle contact point on medial side 5130 of module 5024,identify a lateral condyle contact point on lateral side 5132 of module5024, and measure contact point rotation of surgical apparatus 5000 toname but a few parameters that can be provided. In one embodiment, cover5126 or cover 5128 distributes loading to underlying load sensors inmodule 5024. In one embodiment, module 5024 can be used after removingsurgical apparatus 5000 from the knee joint in a trialing process withinstalled prosthetic components of the knee joint to take furthermeasurements.

Module 5024 couples to and is retained by femoral support 5008. Module5024 has at least one retaining feature. In one embodiment, module 5024has a retaining feature 5114 that couples to an opening 5134 formed infemoral support 5008. In one embodiment, module 5024 is tilted to allowretaining feature 5114 to be placed into opening 5134 and then released.Sidewalls of femoral support 5008 prevent module 5024 from moving duringa distraction or measurement process. In one embodiment, module 5024cannot be removed unless module 5024 is tilted upward from surface 5116of femoral support 5008 such that module 5024 clears the sidewalls offemoral support 5008 and then is moved such that retaining feature 5114is no longer within opening 5134.

Femoral support 5008 couples to medial support structure 5106 andlateral support structure 5108 respectively at a first pivot point and asecond pivot point. Rotating medial tilting screw 5110 raises or lowersmedial support structure 5106 to change a medial-lateral tilt of femoralsupport 5008. Similarly, rotating lateral tilting screw 5112 raises orlowers lateral support structure 5108 to change the medial-lateral tiltof femoral support 5008. The first and second pivot points pivot whenthe height of the medial compartment differs from the height of thelateral compartment. Loading applied to femoral support 5008 duringdistraction is distributed through the first and second pivot points ofsurgical apparatus 5000. In one embodiment, the first pivot pointcomprises a pin 5118 extending from femoral support 5008 on a medialside that fits into an opening 5122 at a proximal end of medial supportstructure 5106. In one embodiment, the second pivot point comprises apin 5120 extending from femoral support 5008 on a lateral side that fitsinto an opening 5124 at a proximal end of lateral support structure5108. Openings 5122 and 5124 have bearing surfaces that respectivelyallow pins 5118 and 5120 to rotate thereby pivoting femoral support5008.

FIG. 55 is an illustration of surgical apparatus 5000 showing bottomsurfaces of femoral support 5008 and tibial support 5006 in accordancewith an example embodiment. Typically, surgical apparatus 5000 isinserted into the musculoskeletal system at the minimum height. In theexample, surgical apparatus 5000 is shown in the minimum height and isconfigured to be inserted into a knee joint before increasing thedistraction height. In one embodiment, a distraction height correspondsto a measurement of a distance between bottom surface 5142 of tibialsupport 5006 and a surface of covers 5126 or 5128 as indicated by doublesided arrow 5174. In one embodiment, the minimum height of surgicalapparatus 5000 occurs when handle 5094 is rotated such that bottomsurface 5170 of femoral support 5008 is co-planar to bottom surface 5142of tibial support 5006.

In general, surgical apparatus 5000 as shown in FIG. 55 is set to theminimum height. Femoral support 5008 fits within the opening of U-shapedstructure 5152 at the minimum height. In one embodiment, medial supportstructure 5106 and lateral support structure 5108 couple to spacer 5140at the minimum height. Medial support structure 5106 and lateral supportstructure 5108 are positioned at the same height when coupled to spacer5140. In one embodiment, there is a gap between medial support structure5106 and cap 5062. Similarly, there is a gap between lateral supportstructure 5108 and cap 5062. Medial support structure 5106 and lateralsupport structure 5108 can move towards cap 5062 but cannot move towardsbase 5060 because spacer 5140 prevents movement at the minimum height.In one embodiment, a portion 5172 of femoral support 5008 overliessurface 5144 of U-shaped structure 5152. A peripheral surface of theportion 5172 of femoral support 5008 couples to surface 5144 of U-shapedstructure 5152 when at the minimum height. As mentioned previously,bottom surface 5170 of femoral support 5008 will be co-planar to bottomsurface 5142 of when at the minimum height. Note that there is a gapbetween tibial support holder 5088 and base 5060 at the minimum height.Tibial support holder 5088 cannot be raised at the minimum height.Lowering tibial support holder 5088 by rotating handle 5094 (clockwise)increases the distraction height from the minimum.

FIG. 56A is an illustration of a plurality of femoral supports inaccordance with an example embodiment. In one embodiment, surgicalapparatus 5000 of FIG. 53 is provided in a right leg surgical apparatusand a left leg surgical apparatus having a leg offset that supportspatellar loading over the range of motion for a kinetic assessment thatprovides quantitative measurement data for the installation of aprosthetic right knee joint or a prosthetic left knee joint. In general,bone sizes vary significantly over a large population. Different sizefemoral supports and tibial supports are also provided to accommodatedifferent bone sizes. In FIG. 56A a femoral support 5180, femoralsupport 5008, and a femoral support 5182 respectively correspond tosmall, medium, and large size femoral supports that are suitable for useover a large variation of the population. The surgeon selects and usesan appropriate size femoral support for a bone size of a patient.Femoral support 5180, femoral support 5008, and femoral support 5182 canbe provided in right leg versions and left leg versions. In oneembodiment, right leg versions of femoral support 5180, femoral support5008, and femoral support 5182 cannot be used on surgical apparatus 5000for a left leg. Similarly, left leg versions of femoral support 5180,femoral support 5008, and femoral support 5182 cannot be used onsurgical apparatus 5000 for a right leg. In one embodiment, femoralsupport 5180, femoral support 5008, and femoral support 5182 does nothave an offset can be used in both a right leg and left leg surgicalapparatus 5000 whereby the offset is in surgical apparatus 5000. In oneembodiment, module 5024 fits in each of femoral support 5180, femoralsupport 5008, and femoral support 5182 such that a single module isrequired for a surgical operation independent of the bone size of thepatient.

FIG. 56B illustrates femoral support 5008 in accordance with an exampleembodiment. In one embodiment, femoral support 5008 comprises majorsurface 5116, bottom surface 5170, sidewalls 5184, pin 5120, pin 5118,and opening 5134. In one embodiment, a peripheral surface 5190 offemoral support 5008 is configured to couple to the tibial support whensurgical apparatus is at a minimum height. Pins 5118 and 5120 areconfigured to respectively couple to the medial support structure andthe lateral support structure and allow femoral support 5008 to mediallyand laterally pivot. In one embodiment, pins 5118 and 5120 can be offsetto support patellar loading for a kinetic assessment that generatesquantitative measurement data. Loading applied to femoral support 5008will be distributed through pins 5118 and 5120. Thus, a single pin orpivot is not supporting the entire load.

FIG. 56C illustrates module 5024 being inserted into femoral support5008 in accordance with an example embodiment. In one embodiment, module5024 is a disposable item. Module 5024 includes one or more sensors andis configured to measure one or more parameters related to themusculoskeletal system. Referring briefly to FIG. 15, module 5024includes electronic circuitry 150 and couples to one or more sensors152. In one embodiment, module 5024 is a hermetically sealed deviceincluding a power source configured to power the device for a singleapplication. Module 5024 is configured similarly to module 150. Forexample, module 5024 is configured to measure such parameters asloading, balance, position, alignment, position of load, medial-lateraltilt, anterior-posterior tilt, and movement when placed in surgicalapparatus 5000. In one embodiment, loading applied to a medial side andloading applied to a lateral side of measurement module 5024 is measuredand transmitted to computer 5026 of FIG. 53. In one embodiment, thequantitative measurement data from surgical apparatus 5000 and module5024 is used to support one or more bone cuts to install one or moreprosthetic components.

Module 5024 can be used later in the installation prior to a finalinstallation of the prosthetic components to confirm quantitativemeasurements of the installation after one or more final prostheticcomponents have been installed on the bone cuts made with surgicalapparatus 5000. Module 5024 can be removed from surgical apparatus 5000and then placed into a shim such that the shim and module 5024 forms atrial prosthetic component substantially equal to a final prostheticcomponent. The trial prosthetic component is then inserted into theprosthetic joint to take further measurements using the one or moresensors of module 5024 to verify installation parameters previouslymeasured. Once confirmed that the measurements are within predeterminedacceptable parameter ranges a final prosthetic component can beinstalled in the prosthetic joint. The final prosthetic component willhave similar or equal measurements since it will have be substantiallyequal in shape and size as the trial prosthetic component. Module 5024is disposed of after the surgical procedure has been completed.

Module 5024 couples to a major surface 5116 of femoral support 5008. Inone embodiment, module 5024 is non-symmetrical about the medial-lateralaxis. For example, module 5024 can only be inserted one way into a rightknee joint femoral support 5008. An opposing side of module 5024 isvisible when inserted into a left knee joint femoral support 5008. Inone embodiment, module 5024 fits into all left and right knee jointfemoral supports such that a single module is used during an operationon the musculoskeletal system independent of the type or size of thefemoral support. Module 5024 has at least one retaining feature toretain module 5024 within femoral support 5008. In one embodiment,retaining feature 5114 is a tab that extends from a posterior side ofmodule 5024. An opening 5134 in femoral support 5008 is configured toreceive retaining feature 5114. Module 5024 is angled to clear thesidewalls 5184 of femoral support 5008 such that retaining feature 5114can be inserted into opening 5134 of femoral support 5008. Module 5024can be dropped or placed into femoral support 5008 once retainingfeature 5114 is in opening 5134 of femoral support 5008. Retainingfeature 5114 and sidewalls 5184 of femoral support 5008 prevent movementof module 5024 during a measurement process.

Module 5024 has a medial side 5130 and a lateral side 5132. In oneembodiment, medial side 5130 of module 5024 has raised regions 5186 thathave a surface above the major medial side surface. Similarly, lateralside 5132 of module 5024 has raised regions 5188 that a surface abovethe major medial side surface. In one embodiment, load sensors underlieraised regions 5186 and 5188. The position of the load sensors are knownwithin module 5024. A load magnitude and a position of applied load canbe calculated from the load values and position of the load sensorsunderlying raised region 5186 and 5188 respectively on medial side 5130and lateral side 5132. The calculation of the load magnitude and theposition of applied load on medial side 5130 and lateral side 5132 iscalculated by the computer as shown in FIG. 53 after receivingmeasurement data from each load sensor from module 5024. Note that themedial side and the lateral sides are the same side when module 5024 isflipped over to use on an opposite type (e.g. right knee to left knee).

FIG. 57 is an illustration of cover 5126 and cover 5128 prior tocoupling to module 5024 in accordance with an example embodiment. Cover5126 and cover 5128 are configured to respectively couple to medial side5130 and lateral side 5132 of module 5024. In the example, femoralsupport 5008 is configured for a left knee insertion. As mentionedpreviously, module 5024 is non-symmetrical having medial side 5130 ofmodule 5024 having a different shape, area, or contour than lateral side5132 of module 5024. In one embodiment, cover 5126 has a different shapeor area than cover 5128. In one embodiment, covers 5126 and 5128comprise a rigid material such as metal, metal alloy, a compositematerial, of a polymer material. In one embodiment, covers 5126 and 5128do not flex or bend when loaded. Covers 5126 and 5128 respectively areconfigured to distribute loading to raised regions 5186 on medial side5130 and raised regions 5188 on lateral side 5132 of module 5024. In oneembodiment, raised regions 5186 and 5188 extend above sidewalls 5184 offemoral support 5008 such that covers 5126 and 5128 couple to raisedregion 5186 and 5188 and not sidewalls 5184. In one embodiment, covers5126 and 5128 overlie the major surfaces of medial side 5130 and lateralside 5132 of module 5024. In the example, a medial condyle and a lateralcondyle of a femur respectively couple to cover 5126 on medial side 5130of module 5024 and cover 5128 on lateral side 5132 of module 5024. Themedial and lateral condyles of the femur respectively apply a force,pressure, or load to sensors underlying raised regions 5186 and 5188.Electronic circuitry within module 5024 couples to one or more sensorsand transmits quantitative measurement data to a computer for viewing bythe surgical team. Covers 5126 and 5128 can be retained to module 5024or femoral support 5008 to prevent movement of covers 5126 and 5128.

FIG. 58 is an illustration of femoral support 5008 being coupled tomedial support structure 5106 and lateral support structure 5108 inaccordance with an example embodiment. The tibial support and the tibialsupport holder are not shown in the illustration to allow detail of theoperation of distraction mechanisms 5012 and 5014 to be shown. Module5024 is coupled to femoral support 5008. Covers 5126 and 5128 couple tomodule 5024 to distribute loading to underlying load sensors in module5024. Pin 5118 and pin 5120 respectively extend from the medial side andthe lateral side of femoral support 5008. In one embodiment, pins 5118and 5120 are cylindrical to support movement or rotation of femoralsupport 5008.

Distraction mechanism 5012 comprises medial support structure 5106,anterior medial guide shaft 5064, posterior medial guide shaft 5068,base 5060, cap 5062, spacer 5140, and screw 5110. Distraction mechanism5012 of surgical apparatus 5000 raises or lowers the height of themedial compartment of a knee joint. Medial support structure 5106couples to and moves on a trajectory determined by anterior medial guideshaft 5064 and posterior medial guide shaft 5068. Rotating screw 5110raises or lowers medial support structure 5106. In one embodiment,rotating screw 5110 clockwise raises medial support structure 5106.Conversely, rotating screw 5110 counterclockwise lowers medial supportstructure 5106 unless spacer 5140 and base 5060 prevent movement.

Distraction mechanism 5014 comprises lateral support structure 5108,anterior lateral guide shaft 5066, posterior lateral guide shaft 5070,base 5060, cap 5062, spacer 5140, and screw 5112. Distraction mechanism5014 of surgical apparatus 5000 raises or lowers the height of thelateral compartment of a knee joint. Lateral support structure 5108couples to and moves on a trajectory determined by anterior lateralguide shaft 5066 and posterior lateral guide shaft 5070. Rotating screw5112 raises or lowers lateral support structure 5108. In one embodiment,rotating screw 5112 clockwise raises lateral support structure 5108.Conversely, rotating screw 5112 counterclockwise lowers lateral supportstructure 5108 unless spacer 5140 and base 5060 prevent movement.

Cage system 5011 comprises medial guide shaft 5064, posterior medialguide shaft 5068, anterior lateral guide shaft 5066, posterior lateralguide shaft 5070, cap 5062, and base 5060. In one embodiment, medialguide shaft 5064, posterior medial guide shaft 5068, anterior lateralguide shaft 5066, posterior lateral guide shaft 5070 are parallel to oneanother. Base 5060 couples to the distal ends of anterior medial guideshaft 5064, anterior lateral guide shaft 5066, posterior medial guideshaft 5068, and posterior lateral guide shaft 5070. Cap 5062 couples tothe proximal ends of anterior medial guide shaft 5064, anterior lateralguide shaft 5066, posterior medial guide shaft 5068, and posteriorlateral guide shaft 5070. Medial guide shaft 5064 and posterior medialguide shaft 5068 couples through openings in medial support structure5012. Screw 5110 couples through cap 5062 to a threaded opening inmedial support structure 5106. Anterior lateral guide shaft 5066 andposterior lateral guide shaft 5070 couples through opening in lateralsupport structure 5014. Screw 5112 couples through cap 5062 to athreaded opening in lateral support structure 5108. As shown, spacer5140 couples between base 5060 and medial support structure 5106 orlateral support structure 5108. In one embodiment, a minimum heightmedial compartment or a minimum height lateral compartment correspondsto medial support structure 5012 or lateral support structure 5104coupled to spacer 5140 and base 5060 such that screws 5110 or 5112respectively cannot be rotated to move medial support structure 5012 orlateral support structure away from cap 5062. Screws 5110 or 5112 can berotated to respectively move medial support structure 5106 or lateralsupport structure 5108 towards cap 5062 as a gap exists between cap 5062and medial support structure 5106 or lateral support structure 5108 tosupport movement to adjust a medial or lateral compartment height.

Pins 5118 and 5120 can have a bearing surface that supports rotationalmovement. Pin 5118 and pin 5120 respectively couple within opening 5122in medial support structure 5106 and opening 5124 in lateral supportstructure 5124. Surfaces within openings 5122 and 5124 can also bebearing surfaces to support rotational movement. Pin 5118 within opening5122 is a first pivot point that allows femoral support structure 5008to rotate medially or laterally. Pin 5120 within opening 5124 is asecond pivot point that allows femoral support structure 5008 to alsorotate medially or laterally. Loading applied to femoral support 5008 isdistributed between the first and second pivot points thereby reducingthe load distribution on each pivot point. Reducing load pivot pointloading increases mechanical reliability of operation of surgicalapparatus 5000 and improves measurement performance as flexing andtorsional forces are reduced as the load is distributed.

FIG. 59A is an illustration of surgical apparatus 5000 showing tibialsupport 5006 being coupled to tibial support holder 5088 in accordancewith an example embodiment. In one embodiment, distraction mechanism5010 comprises tibial support 5006, tibial support holder 5088, anteriormedial guide shaft 5064, anterior posterior guide shaft 5066,distraction lead screw 5092, base 5060, cap 5062, and handle 5094. Inone embodiment, distraction mechanism 5010 raises or lowers the medialand lateral compartments simultaneously and by the same amount. Tibialsupport structure 5008 moves on and along a trajectory determined byanterior medial guide shaft 5064 and anterior lateral guide shaft 5066.In one embodiment, anterior medial guide shaft 5064 and anterior lateralguide shaft 5066 are parallel to one another. Base 5060 couples to thedistal ends of anterior medial guide shaft 5064 and anterior lateralguide shaft 5066. Cap 5062 couples to the proximal ends of anteriormedial guide shaft 5064 and anterior lateral guide shaft 5066. Threadedstructure 5090 couples to or is part of tibial support structure 5088. Aproximal end of distraction lead screw 5092 couples through an openingin base 5060 to threaded structure 5090. Handle 5094 couples to a distalend of distraction lead screw 5092 to allow a user to hold surgicalapparatus 5000 and distract the medial and lateral compartments of aknee joint simultaneously. Rotating handle 5094 turns distraction leadscrew 5092 to raise or lower tibial support holder 5088 and therebyraise or lower tibial support 5006 which couples to tibial supportholder 5088.

Similar to femoral support 5008, tibial support 5006 is a removablestructure for coupling different size tibial supports to distractionmechanism 5010. In one embodiment, tibial support comes in a large,medium, and small size that can accommodate the variation of bone sizesover a large portion of the population. Tibial support 5008 includessupport structure 5100 having retaining clip 5018 on the medial side.Support structure 5100 couples to and extends from the medial and thelateral side of tibial support structure 5088. In one embodiment,support structure 5100 is formed as part of tibial support structure5088. Although not visible, tibial support structure 5088 has a secondsupport structure 5100 having retaining clip 5018 on the lateral side.Support structures 5100 are designed to support and retain arms 5150 oftibial support 5006 to tibial support structure 5000. In one embodiment,tibial support 5006 has a medial arm and a lateral arm. In oneembodiment, tibial support 5006 couples to tibial support holder 5088 inan over and under configuration. Arms 5150 each couple over supportstructure 5100 while structure 5102 of tibial support 5006 couples undertibial support holder 5088 into opening 5104. The over and underconfiguration holds tibial support 5006 to tibial support holder 5088 atthe predetermined medial and lateral compartment heights under loadingby the knee joint during distraction.

In FIG. 59B, arm 5150 is shown positioned in relation to retaining clip5018 prior to coupling. As disclosed, coupling of arm 5150 of tibialsupport 5006 to support structure 5100 of tibial support holder 5088 isthe same on the medial or lateral sides. Arm 5150 extends past supportstructure 5100. Retaining structure 5098 of arm 5150 is placed pastsupport structure 5100. Arm 5150 is configured to couple to supportstructure 5100 once retaining structure 5098 is past support structure5100 as indicated by arrow 5201. Arm 5150 is supported by supportstructure 5100 and retaining structure 5098 is configured to preventremoving tibial support 5006 from surgical apparatus 5000. Arm 5150includes a cavity 5096 configured to couple to retaining clip 5018.Retaining clip 5018 has a raised region 5200 that faces cavity 5096 thatis configured to fit within cavity 5096 of arm 5150 to retain andprevent movement once engaged. In one embodiment, raised region 5200 isshaped identical to at least a portion of cavity 5096 and is configuredto fit within cavity 5096.

Clip 5018 pivots as shown in FIG. 59C to allow clearance for arm 5150 tomove past support structure 5100. In one embodiment, a user presses adistal portion of clips 5018 on both sides of support structure 5100 toprovide clearance to move arms 5150 between tibial support holder 5088and clips 5018. Clip 5018 and raised region 5200 is shown providingclearance for arm 5150 as indicated by arrow 5203 when a distal portionof clip 5018 is pressed. Arm 5150 can couple to support structure 5100once retaining structure 5098 is past support structure 5100 asindicated by arrow 5201. In one embodiment, clips 5018 can be springloaded such that a force is applied to a distal end of clip 5018 tocreate the clearance. Arm 5150 can then couple to support structure 5100in the over and under configuration disclosed herein above.

Clip 5018 can be released as shown in FIG. 59D when arm 5150 couples toa support ledge of support structure 5100. Raised region 5200 of clip5018 will move towards cavity 5096 when released as indicated by arrow5205. In one embodiment, arm 5150 also couples to a side wall of tibialsupport holder 5088. In one embodiment, releasing clip 5018 placesraised regions 5200 into cavity 5096 of arm 5150. In one embodiment,fitting raised regions 5200 into cavities 5096 moves arms 5150 in anoptimal position for retention. In one embodiment, raised region 5200has a three dimensional shape that that fits within an identicallyshaped cavity 5096 such that clip 5018 locks into place when released.The position of clip 5018 in relation to cavity 5096 in the lockedposition corresponds to an edge of retaining feature 5098 coupling tosupport structure 5100 as shown in FIG. 59D. As mentioned the springforce of clips 5018 can hold raised region 5200 into cavity 5096 of arm5150. Alternatively, a magnetic force or magnetic materials can be usedto retain clip 5200 within cavity 5096 where at least one of retainingclip 5200 or cavity walls within cavity 5096 are magnetic and the otheris a ferrous material. As mentioned previously, clips 5018 couple toarms 5150 on the medial and lateral sides of tibial support 5006. Thus,what is disclosed above occurs simultaneously on the medial and lateralsides when arms 5150 of tibial support 5006 couple to tibial supportholder 5088.

FIG. 60 is a top view of surgical apparatus 5000 having an offset for aright knee joint and an offset for a left knee joint in accordance withan example embodiment. In the example, surgical apparatus 5000 isprovided in a right knee surgical apparatus 5210 and a left kneesurgical apparatus 5212. The right knee surgical apparatus 5210 has anoffset towards the medial side of the right knee when inserted into theright knee joint. The left knee surgical apparatus 5212 has an offsettowards the medial side of the left knee when inserted into the kneejoint. Operation of surgical apparatus 5000 as disclosed herein above isidentical for right knee surgical apparatus 5210 or left knee surgicalapparatus 5212. Thus, surgical apparatus 5000 can be separate devicesfor a left knee joint or a right knee joint. The components comprisingright knee apparatus 5210 and left knee apparatus 5212 are the sameexcept for components introducing the offset. In one embodiment, theoffset can be placed in one of or all of medial support structure 5106,lateral support structure 5108, femoral support 5008, and tibial support5006 for the right knee or the left knee surgical apparatus. The offsetof surgical apparatus 5000 allows the patella or extensor mechanism tobe anatomical positioned while surgical apparatus 5000 is placed in theknee joint. Alternatively, a single surgical apparatus could be usedwhereby it is assembled prior to surgery with medial support structure5106, lateral support structure 5108, femoral support 5008, or tibialsupport 5006 for the left or right knee joint. Typically, surgicalapparatus 5210 and 5212 will be provided in a surgical environment. Oncesurgical apparatus 5000 is in the knee joint, the patella can berepositioned on the knee joint. Thus, patellar loading is incorporatedinto all measurements such as alignment, loading, or balance that affectprosthetic component installation for a true kinetic assessment andprosthetic component installation.

FIG. 61 is an illustration of distraction mechanism 5010 of surgicalapparatus 5000 in accordance with an example embodiment. Distractionmechanism 5010 comprises tibial support 5006, tibial support holder5088, anterior medial guide shaft 5064, anterior lateral guide shaft5066, base 5060, cap 5062, distraction lead screw 5092, and handle 5094.Cap 5062 couples to a proximal end of anterior medial guide shaft 5064and a proximal end of anterior lateral guide shaft 5066. Screw 5080couples cap 5062 to anterior medial guide shaft 5064. Screw 5082 couplescap 5062 to anterior lateral guide shaft 5066. Base 5060 couples to adistal end of anterior medial guide shaft 5064 and a distal end ofanterior lateral guide shaft 5066. Referring briefly to FIG. 55, screw5072 couples base 5060 to anterior medial guide shaft 5064. Screw 5074couples base 5060 to anterior lateral guide shaft 5066. Anterior medialguide shaft 5064 and anterior lateral guide shaft 5066 respectivelycouples through a medial opening and lateral opening of tibial supportholder 5088. Tibial support holder 5088 is configured to move on andaligned to the trajectory of anterior medial guide shaft 5064 andanterior lateral guide shaft 5066. Anterior medial guide shaft 5064 andanterior lateral guide shaft 5066 are parallel to one another.Distraction lead screw 5092 couples through base 5060 to threadedstructure 5090 of tibial support holder 5088. Handle 5094 couples to adistal end of distraction lead screw 5092.

Rotating handle 5094 is configured to move tibial support holder 5088relative to base 5060. In one embodiment, rotating handle 5094 clockwise(as indicated by arrow 5218) is configured to move tibial support holder5088 towards base 5060. Tibial support 5006 is coupled to tibial supportholder 5088 and moves with tibial support holder 5088. Conversely,rotating handle 5094 counter-clockwise moves tibial support holder 5088in an opposite direction away from base 5060. As shown in FIG. 61,handle 5094 is rotated in a clockwise direction thereby rotatingdistraction lead screw 5092 within threaded structure 5090 of tibialsupport holder 5088. Tibial support holder 5088 moves towards base 5060as indicated by arrow 5220. Similarly, tibial support 5006 moves in adirection indicated by arrow 5222. Thus, the medial and lateralcompartment heights with tibial support 5006 moving towards base 5060.Conversely, tibial support 5006 moving in the opposite direction asarrow 5222 will reduce the height of the medial and lateralcompartments. In one embodiment, a plane of tibial support 5006 isperpendicular to a plane comprising anterior medial guide shaft 5064 andanterior lateral guide shaft 5066. In one embodiment, distractionmechanism 5010 raises or lowers the medial compartment and the lateralcompartment of the knee joint by an equal distance.

Referring to FIGS. 58 and 61, the height or change of height of themedial and lateral compartments can be measured by a mechanical gaugethat couples to distractor mechanisms 5010, 5012, or 5014. In general, amechanical gauge couples to moving parts of surgical apparatus 5000 andincludes an indicator that shows a measurement of a parameter based onthe movement of the components. The indicator can be electrical ormechanical. The mechanical gauge can be configured to measure a distancebetween a bottom surface of tibial support 5006 and a surface of cover5126 or a surface of plate 5128. A second mechanical gauge can beconfigured to measure the medial-lateral tilt of femoral support 5008.The medial-lateral tilt corresponds to a position difference of pin 5120and 5118 or the tilt of femoral support 5008. In one embodiment, themechanical gauges will have an indicator that allows the surgeon to readthe compartment heights and medial-lateral tilt on surgical apparatus5000.

Electronic circuitry 150 of FIG. 15 can be coupled on or in surgicalapparatus 5000. Electronic circuitry 150 will couple to one or moresensors for measuring a parameter and transmitting quantitativemeasurement data to a computer as disclosed in FIG. 53 and furtherdescribed in detail herein above for other variations of the surgicalapparatus or distractor. A computer 5026 that is configured to receiveand provide the quantitative measurement data to the surgeon. Computer5026 includes a display 5028 for providing quantitative measurement datato the surgical team in the operating room in real-time. In oneembodiment, a Hall Effect sensor 204 or linear Hall sensor 222 of FIGS.16-20 can be configured to measure femoral support tilt or compartmentheight on surgical apparatus 5000. Hall Effect sensor 204 and linearhall sensor 222 couple to electronic circuitry 150. The components ofFIGS. 15-20 will be adapted for use on surgical apparatus 5000 toillustrate how it can be measured. In one embodiment, magnet 200 can becoupled to pin 5118 or pin 5120 such that magnet 200 rotates from areference position. In one embodiment, the reference positioncorresponds to the medial-lateral compartment heights being equal. HallEffect sensor 204 is located within the magnetic field of magnet 200. Asmagnet 200 rotates Hall Effect sensor 204 measures the amount ofrotation which is then transmitted by electronic circuitry 150 anddisplayed on display 5028 of computer 5026. Display 5028 can numericallydisplay the amount of rotation or have an indicator bar to display themedial-lateral tilt as disclosed in FIG. 36.

Linear Hall sensor 222 can be used to measure compartment height. LinearHall sensor 222 operates in the presence of a magnetic field like HallEffect sensor 204. A first magnet 220 and a second magnet 220 can berespectively coupled to a medial side and a lateral side of femoralsupport 5008. Similarly, a first linear Hall sensor 222 and a secondlinear hall sensor 222 can be respectively coupled to the medial sideand the lateral side of tibial support 5006 such that first linear Hallsensor 222 is within the magnetic field of the first magnet 220 and thesecond linear Hall sensor 222 is within the magnetic field of the secondmagnet 220. The strength of the magnetic field measured by the first andsecond linear Hall sensors 222 corresponds to the distance. The medialcompartment height and the lateral compartment height can be displayedas a numerical number on display 5028 of computer 5026 or displayedvisually such as a bar graph as shown in FIG. 20. Alternatively, asingle linear Hall sensor 222 can be used. Magnet 220 can be placedbetween the medial and lateral sides of femoral support 5008. Thus,linear Hall sensor 222 measures the average of the medial and lateralcompartment heights. Measurement data from Hall effect sensor 204corresponding to the medial-lateral tilt can be used with themeasurement data from the single linear Hall sensor 222 to calculate theheight of the medial compartment and the lateral compartment usingcomputer 5026.

FIG. 62 is an illustration of distraction mechanism 5012 of surgicalapparatus 5000 in accordance with an example embodiment. Distractionmechanism 5012 comprises femoral support 5008, medial support structure5106, anterior medial guide shaft 5064, posterior medial guide shaft5068, base 5060, cap 5062, and medial tilting screw 5110. Cap 5062couples to a proximal end of anterior medial guide shaft 5064 andposterior medial guide shaft 5068. Screw 5080 couples cap 5062 toanterior medial guide shaft 5064. Screw 5084 couples cap 5062 toposterior medial guide shaft 5068. Base 5060 couples to a distal end ofanterior medial guide shaft 5064 and a distal end of posterior medialguide shaft 5068. Referring briefly to FIG. 55, screw 5072 couples base5060 to anterior medial guide shaft 5064. Screw 5076 couples base 5060to posterior medial guide shaft 5068. Anterior medial guide shaft 5064and posterior medial guide shaft 5068 respectively couples through ananterior opening and posterior opening of medial support structure 5106.Medial support structure 5106 is configured to move on and aligned tothe trajectory of anterior medial guide shaft 5064 and posterior medialguide shaft 5068. Anterior medial guide shaft 5064 and posterior medialguide shaft 5068 are parallel to one another. Medial tilting screw 5110couples through cap 5062 to a threaded opening in medial supportstructure 5106. Femoral support 5008 couples to medial support structure5106 through a first pivot point that supports medial side tilting offemoral support 5008. Referring briefly to FIG. 54, the first pivotpoint comprises pin 5118 of femoral support 5008 rotatably coupling toan opening 5122 of lateral support structure 5108.

In one embodiment, medial tilting screw 5110 is configured to movemedial support structure 5106 relative to cap 5062. Medial tilting screw5110 couples to the threaded opening in medial support structure 5106.In one embodiment, rotating medial tilting screw 5110 clockwise (asindicated by arrow 5232) is configured to move medial support structure5106 towards cap 5062. Femoral support 5008 couples to medial supportstructure 5106 through the first pivot point. In the example ofclockwise rotation of medial tilting screw 5110, the medial side offemoral support 5008 is raised towards cap 5062 thereby changing themedial-lateral tilt. Medial support structure 5106 moves towards cap5062 as indicated by arrow 5234. As shown, the height of the medialcompartment is greater than the height of the lateral compartment.Similarly, femoral support 5008 on the medial side moves in a directionindicated by arrow 5236. Conversely, rotating medial tilting screw 5110counter-clockwise moves medial support structure 5106 in an oppositedirection away from cap 5062 thereby changing the medial-lateral tilt.In one embodiment, distraction mechanism 5012 is configured to increaseor decrease the height of the medial compartment of the knee joint. Theheight or change of height of the medial compartment can be measured byelectronic circuitry and sensors as disclosed herein above.Alternatively, the height or change of height of the medial and lateralcompartment can measured by mechanical gauges coupled to surgicalapparatus 5000.

FIG. 63 is an illustration of distraction mechanism 5014 of surgicalapparatus 5000 in accordance with an example embodiment. Distractionmechanism 5014 comprises femoral support 5008, lateral support structure5108, anterior lateral guide shaft 5066, posterior lateral guide shaft5070, base 5060, cap 5062, and lateral tilting screw 5112. Cap 5062couples to a proximal end of anterior lateral guide shaft 5066 andposterior lateral guide shaft 5070. Screw 5082 couples cap 5062 to theproximal end of anterior lateral guide shaft 5066. Screw 5086 couplescap 5062 to the proximal end of posterior lateral guide shaft 5070. Base5060 couples to a distal end of anterior lateral guide shaft 5066 and adistal end of posterior lateral guide shaft 5070. Referring briefly toFIG. 54, screw 5074 couples base 5060 to a distal end anterior lateralguide shaft 5066. Screw 5078 couples base 5060 to a distal end ofposterior lateral guide shaft 5070. Anterior lateral guide shaft 5066and posterior lateral guide shaft 5070 respectively couples through ananterior opening and posterior opening of lateral support structure5108. Lateral support structure 5108 is configured to move on andaligned to the trajectory of anterior lateral guide shaft 5066 andposterior lateral guide shaft 5070. In one embodiment, anterior lateralguide shaft 5066 and posterior lateral guide shaft 5070 are parallel toone another. Lateral tilting screw 5112 couples through cap 5062 to athreaded opening within lateral support structure 5108. Femoral support5008 couples to lateral support structure 5108 through a second pivotpoint that supports lateral side tilting of femoral support 5008.Referring briefly to FIG. 54, the second pivot point comprises pin 5120of femoral support 5008 rotatably coupling to an opening 5124 of lateralsupport structure 5108.

In one embodiment, medial tilting screw 5112 is configured to movelateral support structure 5108 relative to cap 5062. Lateral tiltingscrew 5112 couples to the threaded opening in lateral support structure5108. In one embodiment, rotating lateral tilting screw 5112 clockwise(as indicated by arrow 5230) is configured to move lateral supportstructure 5108 towards cap 5062. Femoral support 5008 couples to lateralsupport structure 5108 through the second pivot point. The lateral sideof femoral support 5008 is raised towards cap 5062 thereby changing themedial-lateral tilt. Lateral support structure 5108 moves towards cap5062 as indicated by arrow 5238. As shown, the height of the lateralcompartment is greater than the height of the medial compartment.Similarly, femoral support 5008 on the lateral side moves in a directionindicated by arrow 5240. Thus, rotating lateral tilting screw 5112clockwise increases the lateral compartment height. Conversely, rotatingmedial tilting screw 5112 counter-clockwise moves lateral supportstructure 5108 in an opposite direction away from cap 5062 therebychanging the medial-lateral tilt. In one embodiment, distractionmechanism 5014 raises or lowers the lateral compartment of the kneejoint. The height or change of height of the lateral compartment can bemeasured by electronic circuitry and sensors as disclosed herein above.Alternatively, the height or change of height of the medial and lateralcompartment can measured by mechanical gauges coupled to surgicalapparatus 5000.

FIG. 64 is an illustration of a surgical apparatus 6000 in accordancewith an example embodiment. Surgical apparatus 6000 is similar tosurgical apparatus 5000 disclosed herein above and comprises many of thesame components. Surgical apparatus 6000 is configured for use in themusculoskeletal system. In one embodiment, surgical apparatus comprisesat least one sensor for measuring a parameter. Surgical apparatus 6000can be adapted for use in a kinetic assessment for providingquantitative measurement data from the musculoskeletal system, knee,hip, shoulder, spine, ankle, wrist, hand, foot, or bone. In oneembodiment, surgical apparatus 6000 is configured to supportinstallation of a knee joint that includes quantitative measurement ofapplied load, position, component rotation, height, medial-lateral tilt,position of load, or alignment over a range of motion and in real-time.In one embodiment, the quantitative measurement data is used to cut bonefor installing a prosthetic component, reduce leg alignment error,optimize knee loading, optimize knee balance, optimize contact pointlocation, improve range of motion, or support ligament tensioning. Thequantitative measurement data is received by computer 5026 and displayedon display 5028 in real-time such that adjustments that change measuredparameters can be incorporated into the installation in real-time. Inone embodiment, at least one adjustment is made using surgical apparatus6000 that adjusts a parameter such that the change in the parameter ismeasured and improves the prosthetic joint installation. In general,surgical apparatus 6000 differs from surgical apparatus 5000 of FIG. 53in that measurements are made by separate measurement modules on amedial and lateral side of surgical apparatus 6000. Surgical apparatus5000 uses a single measurement module. Loading on the medial or thelateral side of surgical apparatus 6000 is supported by independent pinsthat do not rotate. Conversely, medial-lateral loading on surgicalapparatus 5000 is configured to pivot through two pivot points andloading is distributed between the two pivot points as disclosed hereinabove. In one embodiment, surgical apparatus 6000 has an offset thatsupports patella loading of the knee joint. The offset supportsplacement of the patella on a lateral side of the knee joint and allowsthe patella to be placed back on the knee joint after distractor 6000 isinserted. The patella loads the knee joint and is taken into account inall the quantitative measurement data and subsequent steps taken priorto the knee joint installation to provide a true kinetic assessment. Inone embodiment, the offset is specific for the left knee and the rightknee. In one embodiment, surgical apparatus 6000 comprises two separatedevices, one for the left knee and one for the right knee. In theexample, the offset of surgical apparatus 6000 is configured for a leftknee joint. As described herein, description of the operation andcomponents will apply to both the left knee and right surgical apparatus6000.

Surgical apparatus 6000 has three distracting mechanisms configured toincrease a medial compartment height, a lateral compartment height, orboth simultaneously in accordance with an example embodiment. Ingeneral, surgical apparatus 6000 is configured to support installationof a prosthetic joint of the musculoskeletal system. Surgical apparatus6000 can include, but is not limited to measurement of parameters suchas height, length, width, tilt/slope, position, orientation, alignment,offset, rotation, tension, load magnitude, force, pressure, contactpoint location, displacement, density, viscosity, pH, light, color,sound, optical, vascular flow, visual recognition, humidity, alignment,rotation, inertial sensing, turbidity, bone density, fluid viscosity,strain, angular deformity, vibration, torque, elasticity, motion, andtemperature. Electronic circuitry 150 as disclosed herein in FIG. 15 canbe coupled to the sensors listed above to control a measurement process,generate quantitative measurement data, and transmit the quantitativemeasurement data of surgical apparatus 6000 to the computer 5026.Electronic circuitry 150 of FIG. 15 can be housed on or in surgicalapparatus 6000 that couples to one or more sensors on or in surgicalapparatus 6000. Similarly, electronic circuitry 150 of FIG. 15 can bewithin two or more measurement module having one or more sensors.Computer 5026 with display 5028 can be configured to receive and providequantitative measurement data from multiple measurement systems ormodules each comprising electronic circuitry 150 and one or moresensors. In one embodiment, transmissions can be at differentfrequencies or provided at different times on the same frequency managedby computer 5026.

The three distracting mechanisms of surgical apparatus 6000 aredistraction mechanism 5010, distraction mechanism 5012, and distractionmechanism 5014. The three distractor mechanisms are the same and operateidentically to the distractor mechanisms disclosed for distractor 5000herein above. The three distractor mechanisms are supported and alignedby a cage system 5011. Cage system 5011 comprises a cap 5062, ananterior medial guide shaft 5064, an anterior lateral guide shaft 5066,a posterior medial guide shaft 5068, a posterior lateral guide shaft5070, and a base 5060. In one embodiment, anterior medial guide shaft5064, anterior lateral guide shaft 5066, posterior medial guide shaft5068, and posterior lateral guide shaft 5070 are parallel to one anotherand couple between base 5060 and cap 5062 in a square or rectangularpattern to support movement of distraction mechanism 5010, distractionmechanism 5012, and distraction mechanism 5014. Movement of tibialsupport holder 5088, medial support structure 5106, and lateral supportstructure 5108 are aligned to and guided by cage system 5011 under usercontrol. How tibial support holder 5088, medial support structure 5106,and lateral support structure 5108 couple to cage system 5011 isdisclosed in FIG. 54 herein above. Similarly, screws that couple cagesystem 5011 together are shown in FIG. 54. Details of components ofsurgical apparatus 6000 that are identical to surgical apparatus 5000are disclosed herein above and will not be repeated for brevity. Thecomponents that are identical in surgical apparatus 5000 and 6000 willalso have the same numbering and perform identically. Also, detailprovided about surgical apparatus 6000 and more specifically theidentical components in surgical apparatus 5000 and 6000 also applies tosurgical apparatus 5000.

A spacer 5140 can be used to place medial support structure 5106 andlateral support structure 5108 in a reference position in surgicalapparatus 6000. Spacer 5140 has a predetermined height that determinesthe reference position. Spacer 5140 has a first opening and a secondopening that respectively couples through posterior medial guide shaft5068 and posterior lateral guide shaft 5070 of cage system 5011. Spacer5140 couples between base 5060 and medial support structure 5106.Similarly, spacer 5140 couples between base 5060 and lateral supportstructure 5108. In one embodiment, the reference position is establishedwhen surgical apparatus 6000 is in a minimum height position. In oneembodiment, the minimum height position corresponds to a minimum heightof surgical device 6000 measured from a bottom surface 5142 of tibialsupport 5006 to exposed surfaces of measurement module 6002 ormeasurement module 6004. A first side of spacer 5140 will couple to base5060 and second side of spacer 5140 will couple to medial supportstructure 5106 and lateral support structure 5108. In one embodiment,the minimum height of surgical apparatus 6000 corresponds to a bottomsurface of medial femoral support 6006 or lateral femoral support 6008being co-planar with bottom surface 5142 of tibial support 5006. In oneembodiment, the position of spacer 5140 can be fixed such that spacer5140 remains coupled to base 5060 when medial or lateral compartmentheights are changed.

Distraction mechanism 5010 of surgical apparatus 6000 comprises tibialsupport holder 5088, cage system 5011, distraction lead screw 5092, andhandle 5094. Distraction mechanism 5010 is configured to move tibialsupport 5006 relative to femoral support 5008. In one embodiment, tibialsupport 5006 couples to a prepared bone surface of a proximal end of atibia. In one embodiment, distraction mechanism 5010 simultaneouslydistracts a medial compartment and a lateral compartment of a knee jointby equal amounts. Tibial support holder 5088 comprises a structurehaving a medial opening and a lateral opening. Anterior medial guideshaft 5064 and anterior lateral guide shaft 5066 respectively couplethrough the medial opening and the lateral opening of tibial supportholder 5088. Distraction lead screw 5092 is configured to move tibialsupport holder 5088 under user control. Distraction lead screw 5092couples through an opening in base 5060 to couple to threaded structure5090 of tibial support structure 5088. Threaded structure 5090 has athreaded opening configured to receive distraction lead screw 5092.Distraction lead screw 5092 couples thru the threaded opening ofthreaded structure 5090 to motivate tibial support holder 5088 whenrotated. Rotating handle 5094 engages distraction lead screw 5092 tothreads within threaded structure 5090 of tibial support holder 5088 tomove tibial support holder 5088 along a trajectory defined by anteriormedial guide shaft 5064 and anterior lateral guide shaft 5066. Tibialsupport holder 5088 can move towards or away from base 5060 depending onthe direction of rotation of distraction lead screw 5092. This is shownand described in detail in FIG. 61 disclosed herein above.

Tibial support 5006 couples to tibial support holder 5088. In oneembodiment, tibial support 5006 is supported under load by tibialsupport holder 5088. Retaining clips 5018 on the medial and lateralsides of tibial support holder 5008 are pressed to allow arms 5150 andstructure 5102 of tibial support 5006 to couple to tibial support holder5088. Releasing clips 5018 locks tibial support 5006 to tibial supportholder 5088 into a predetermined position. In one embodiment, tibialsupport 5006 has more than one size and is removable from tibial supportholder 5088. In one embodiment, tibial support 5006 comprises a U-shapedstructure 5152 that has a bottom surface 5142 configured to couple to aprepared bone surface at the proximal end of a tibia. Alternatively,tibial support structure can couple to a proximal end of a natural tibiaor a tibial prosthetic component. In one embodiment, the bottom surface5142 of U-shaped structure 5152 is planar. Removing tibial support 5006from tibial support holder 5088 is an opposite process comprisingpressing retaining clips 5018 to release tibial support 5006 and pullingtibial support 5006 away from tibial support holder 5088.

Distraction mechanism 5012 comprises a medial support structure 5106,cage system 5011, and a medial tilting screw 5110. Distraction mechanism5012 is configured to move medial support structure 5106 relative totibial support 5006. A medial femoral support 6006 is configured tocouple to medial support structure 5106. A pin 6010 extends from medialfemoral support 6006. Pin 6010 is configured to couple to opening 5122of medial support structure 5106. In one embodiment, pin 6010 does notrotate in opening 5122. Pin 6010 is configured to place medial femoralsupport 6006 in a predetermined position. In one embodiment, pin 6010 issquare or rectangular in shape with rounded edges. Pin 6010 can beformed in a shape that allows insertion into opening 5122 in only asingle orientation. Pin 6010 can lock into place when inserted intoopening 5122 but is removable. Similar to tibial support 5006, medialfemoral support 6006 can come in several sizes (example large, medium,and small) that can be used in surgical apparatus 6000 to accommodatedifferent bone sizes. Medial femoral support 6006 has a surface 6014.Measurement module 6002 couples to medial femoral support 6006 and issupported by surface 6014. An exterior surface of measurement module6002 extends above medial femoral support 6006. In one embodiment, theexternal surface of measurement module 6002 is configured to couple to amedial condyle of a knee to support movement of the knee joint. Althoughnot shown, a cover can be placed on measurement module 6002 as shown inFIG. 54.

Measurement module 6002 includes electronic circuitry 150 as disclosedin FIG. 15 herein above. Measurement module 6002 couples to one or moresensors. In one embodiment, measurement module 6002 controls ameasurement process and transmits measurement data to computer 5026. Inone embodiment, measurement module 6002 includes a plurality of loadsensors configured to measure loading applied at predetermined locationsof the external surface of measurement module 6002 by the medial condyleof the knee joint. Computer 5026 is configured to receive themeasurement data from the load sensors and calculate a magnitude ofapplied load by the medial condyle and the position of applied load onthe external surface of measurement module 6002. The placement of theload sensors in measurement module 6002 is similar to that shown for themedial side of module 32 of FIG. 22. As shown in FIG. 22, three loadsensors are used. One difference between module 32 and measurementmodule 6002 is that electronic circuitry 150 of FIG. 15 is placed withinmeasurement module 6002 and is not shared between the medial and lateralsides as shown in FIG. 22. Measurement module 6002 can have raisedregions similar to that shown in FIG. 56C that are aligned with andoverlie each load sensor. The raised regions are reinforced areas thatdirect loading to the load sensors. A raised region of measurementmodule 6002 is configured to distribute loading evenly across a surfaceof a corresponding load sensor for more accurate load measurement.

Raising or lowering medial support structure 5106 changes a height ofthe medial compartment of the knee joint by raising or lowering medialfemoral support 6006 relative to tibial support 5006. Medial supportstructure 5106 includes a first opening, a second opening, and athreaded opening. In one embodiment, a direction of movement of medialsupport structure 5106 is determined by cage system 5011. Anteriormedial guide shaft 5064 couples through the first opening in medialsupport structure 5106. Similarly, posterior medial guide shaft 5068couples through the second opening in medial support structure 5106.Movement and trajectory of medial support structure 5106 are aligned toanterior medial guide shaft 5064 and posterior medial guide shaft 5068.Medial tilting screw 5110 couples through an opening in cap 5062. Medialtilting screw 5110 couples through the opening into the threaded openingof medial support structure 5106. In one embodiment, the threads ofmedial tilting screw 5110 engage with the threads in the threadedopening of medial support structure 5106 to hold medial supportstructure 5106 in a fixed position. The engaged threads between medialtilting screw 5110 and the threaded opening in medial support structure5106 can support loading applied to femoral support 5008 and will notchange the medial compartment height unless medial tilting screw 5110 isrotated. In one embodiment, an Allen wrench can be used to rotate medialtilting screw 5110. Rotating medial tilting screw 5110 can pull medialsupport structure 5106 towards cap 5062 or away from cap 5062 dependingon the direction of rotation. In one embodiment, turning medial tiltingscrew 5110 clockwise raises medial support structure 5106 and medialfemoral support 6006 towards cap 5062. Conversely, turning medialtilting screw 5110 counter clockwise lowers medial support structure andmedial femoral support 6006 away from cap 5062. Thus, rotation of medialtilting screw 5110 is configured to adjust the medial compartment heightand the medial-lateral tilt of surgical apparatus 6000. In oneembodiment, measurement module 6002 can be used after removing surgicalapparatus 6000 from the knee joint in a trialing process with installedprosthetic components of the knee joint to take further measurements.

Distraction mechanism 5014 comprises a lateral support structure 5108,cage system 5011, and a medial tilting screw 5112. Distraction mechanism5014 is configured to move lateral support structure 5108 relative totibial support 5006. A lateral femoral support 6008 is configured tocouple to lateral support structure 5108. A pin 6012 extends from medialfemoral support 6006. Pin 6012 is configured to couple to opening 5124of lateral support structure 5108. In one embodiment, pin 6012 does notrotate in opening 5124. Pin 6012 is configured to place lateral femoralsupport 6008 in a predetermined position. In one embodiment, pin 6012 issquare or rectangular in shape with rounded edges. Pin 6012 can beformed in a shape that allows insertion into opening 5124 in only asingle orientation. Pin 6012 can lock into place when inserted intoopening 5124 but is removable. Similar to tibial support 5006, lateralfemoral support 6008 can come in several sizes (example large, medium,and small) that can be used in surgical apparatus 6000 to accommodatedifferent bone sizes. Lateral femoral support 6008 has a surface 6018.Measurement module 6004 couples to medial femoral support 6008 and issupported by surface 6018. An exterior surface of measurement module6004 extends above lateral femoral support 6008. In one embodiment, theexternal surface of measurement module 6004 is configured to couple to alateral condyle of a knee to support movement of the knee joint.Although not shown, a cover can be placed on measurement module 6004similar to that shown in FIG. 54.

Measurement module 6004 includes electronic circuitry 150 as disclosedin FIG. 15 herein above. Measurement module 6004 couples to one or moresensors. In one embodiment, measurement module 6004 controls ameasurement process and transmits measurement data to computer 5026. Inone embodiment, measurement module 6004 includes a plurality of loadsensors configured to measure loading applied at predetermined locationsof the external surface of measurement module 6004 by the lateralcondyle of the knee joint. Computer 5026 is configured to receive themeasurement data from the load sensors and calculate a magnitude ofapplied load by the lateral condyle and the position of applied load onthe external surface of measurement module 6004. The placement of theload sensors in measurement module 6004 is similar to that shown for thelateral side of module 32 of FIG. 22. As shown in FIG. 22, three loadsensors are used. One difference between module 32 and measurementmodule 6004 is that electronic circuitry 150 of FIG. 15 is placed withinmeasurement module 6004 and is not shared between the medial and lateralsides as shown in FIG. 22. Measurement module 6004 can have raisedregions similar to that shown in FIG. 56C that are aligned with andoverlie each load sensor. The raised regions are reinforced areas thatdirect loading to the load sensors. A raised region of measurementmodule 6004 is configured to distribute loading evenly across a surfaceof a corresponding load sensor for more accurate load measurement.Measurement modules 6002 and 6004 include a position tracking systemthat measures position and alignment of the leg. In one embodiment, theposition tracking system comprises one or more sensors such asaccelerometers, gyroscopes, magnetometers, GPS system, or IMU's(inertial measurement units). In one embodiment, the load sensors usedin surgical apparatus 5000 and 6000 are elastically compressiblecapacitors that can be integrated within flexible interconnect to lowercost, increase reliability, increase uniformity, and sensitivity.Alternatively, load sensors can comprise strain gauges, MEMs device,piezo-resistive sensors, mechanical sensors, polymer sensors, opticalsensors, or ultrasonic sensors. In one embodiment, quantitativemeasurement data from measurement modules 6002 and 6004 is used bycomputer 5026 to calculate leg position, alignment of a bone of the leg,or alignment of the leg relative to a mechanical axis.

Raising or lowering medial support structure 5108 changes a height ofthe lateral compartment of the knee joint by raising or lowering lateralfemoral support 6008 relative to tibial support 5006. Lateral supportstructure 5108 includes a first opening, a second opening, and athreaded opening. In one embodiment, a direction of movement of lateralsupport structure 5108 is determined by cage system 5011. Anteriorlateral guide shaft 5066 couples through the first opening in lateralsupport structure 5108. Similarly, posterior lateral guide shaft 5070couples through the second opening in lateral support structure 5108.Movement and trajectory of lateral support structure 5108 are aligned toanterior lateral guide shaft 5066 and posterior lateral guide shaft5070. Lateral tilting screw 5112 couples through an opening in cap 5062.Lateral tilting screw 5112 couples through the opening into the threadedopening of medial support structure 5108. In one embodiment, the threadsof lateral tilting screw 5112 engage with the threads in the threadedopening of lateral support structure 5108 to hold lateral supportstructure 5108 in a fixed position. The engaged threads between lateraltilting screw 5112 and the threaded opening in lateral support structure5108 can support loading applied to femoral support 5008 and will notchange the lateral compartment height unless lateral tilting screw 5112is rotated. In one embodiment, an Allen wrench can be used to rotatelateral tilting screw 5112. Rotating lateral tilting screw 5112 can pulllateral support structure 5108 towards cap 5062 or away from cap 5062depending on the direction of rotation. In one embodiment, turninglateral tilting screw 5112 clockwise raises lateral support structureand lateral femoral support 6008 towards cap 5062. Conversely, turninglateral tilting screw 5112 counter clockwise lowers lateral supportstructure 5108 and lateral femoral support 6008 away from cap 5062.Thus, rotation of lateral tilting screw 5112 is configured to adjust thelateral compartment height and the medial-lateral tilt of surgicalapparatus 6000. In one embodiment, measurement module 6004 can be usedafter removing surgical apparatus 6000 from the knee joint in a trialingprocess with installed prosthetic components of the knee joint to takefurther measurements.

As mentioned previously, surgical apparatus 6000 has separateindependent paddles for increasing or decreasing the medial compartmentheight or the lateral compartment height relative to tibial support5006. Medial femoral support 6006 and lateral femoral support 6008respectively supports loading on the medial compartment and the lateralcompartment by the medial condyle and the lateral condyle of the kneejoint. The medial and lateral condyles can be natural condyles of thefemur or condyles of a femoral prosthetic component. In one embodiment,loading applied to medial femoral support 6006 and measurement module6002 is coupled through pin 6010 to medial support structure 5106.Similarly, loading applied to lateral femoral support 6008 andmeasurement module 6004 is coupled through pin 6012 to lateral supportstructure 5108. Surgical apparatus 6000 and measurement modules 6002 and6004 support rotation of the leg through a range of motion. Measurementmodules 6002 and 6004 each transmit measurement data to computer 5026where the measurement data is displayed.

The height and medial lateral tilt can be measured by mechanical gaugescoupled to the moving components of surgical apparatus 6000 that affectcompartment height. The benefit of the mechanical gauges are that theyare implemented on apparatus 6000 and do not require electroniccircuitry 150, sensors, or a power source. Similarly, Hall effect sensor204 and linear Hall effect sensor 222 of FIGS. 16-20 can be adapted tomeasure medial or lateral compartment height and medial-lateral tilt ofsurgical apparatus 6000. In one embodiment, the medial-lateral tilt canbe calculated by measuring the height of the medial compartment and theheight of the lateral compartment. The measurement data is sent to thecomputer 5026 and can be displayed as indicated in FIGS. 36-38 in amanner that allows the surgeon to determine height and medial-lateraltilt at a glance. The difference in compartment height corresponds tothe medial-lateral tilt. The angle can be determined from apredetermined point on medial femoral support 6006 (such as the centerof surface 6014 and a predetermined point on lateral femoral support6008 (such as the center of surface 6016). The angle corresponds to aline drawn through the two center points of surface 6014 and 6016.Alternatively, other sensors can be used for measuring compartmentheight or medial-lateral tilt of surgical apparatus 5000 and 6000. Thesesensors could also be adapted to couple to the moving components thatchange the medial and lateral compartment heights. Examples of systemsor sensors measuring distance or height are imaging, optical, laser,altimeter, GPS, MEMs devices, ultrasonic sensors, inertial sensors,magnetic sensors, Eddy current sensors, and light emitting diodes toname but a few. Similarly, an inclinometer, inertial sensors, rotaryencoder, MEMs sensors, magnetic sensors, imaging, optical, laser,altimeter, GPS, ultrasonic sensors, light emitting diodes can be adaptedfor measuring an angle or tilt.

FIG. 65 is a top view of an offset of surgical apparatus 6000 for use ina left knee in accordance with an example embodiment. In the example,surgical apparatus 6000 comprises a left leg surgical apparatus 6050configured for supporting a left leg prosthetic knee joint installation.Left leg surgical apparatus 6050 has an offset that supports placing thepatella to the one side of the knee joint while left leg surgicalapparatus 6050 is inserted. The patella can then be placed back on theleft knee joint with left leg surgical apparatus 6050 in place due tothe offset. Placing the patella on the knee joint while left legsurgical apparatus 6050 is being used loads the knee joint as it wouldonce the prosthetic knee joint has been installed. Thus, loading of thepatella is taken into account in regards to leg alignment, loading, andbalance as left leg surgical apparatus 6050 is used to support a leftleg prosthetic knee joint installation.

Tibial support 5006 of distraction mechanism 5010 couples to cage system5011 in a manner that allows movement of tibial support 5006 underloading of the left knee joint. In one embodiment, a user controlsmovement of tibial support 5006 using distraction mechanism 5010 suchthat a medial and a lateral compartment height of the left knee jointcan be changed. Alternatively, movement of distraction mechanism 5010can be automated such that the medial and lateral compartment height ischanged by motor, pneumatic, electrical, or other mechanical system. Ineither case, measurement data is provided to computer 5026 of FIG. 64for display and analysis.

Medial femoral support 6006 couples to medial support structure 5106.Medial support structure 5106 of distraction mechanism 5012 couples tocage system 5011 in a manner that allows movement of medial femoralsupport 6006 under loading of the left knee joint. Measurement module6002 couples to medial femoral support 6006. In one embodiment, themedial compartment height can be raised or lowered under loading on themedial side of the left knee joint by distraction mechanism 5012. A usercontrols movement of the medial support structure 5106 and therebymedial femoral support 6006. In the example, medial tilting screw 5110couples to medial support structure 5106 through cap 5062 of cage system5011. The user can rotate medial tilting screw 5110 with a wrench wherethe rotation moves medial support structure 5106 towards cap 5062 oraway from cap 5062 depending on the direction of rotation.Alternatively, movement of distraction mechanism 5012 can be automatedsuch that the medial compartment height is changed by motor, pneumatic,electrical, or other mechanical system without the need of a user incontact with surgical apparatus 6000. A measurement module 6002 couplesto medial femoral support 6006. Medial side loading of the left kneejoint is applied to measurement module 6002 and thereby medial femoralsupport 6006. Measurement module 6002 is configured with at least onesensor to generate quantitative measurement data related to the leftknee joint. In one embodiment, measurement module 6002 measures loading,position of load, alignment, and balance. Screws 5080, 5082, 5084, and5086 hold cap 5062 to cage system 5011.

Lateral femoral support 6008 couples to lateral support structure 5108.Lateral support structure 5108 of distraction mechanism 5014 couples tocage system 5011 in a manner that allows movement of lateral femoralsupport 6006 under loading of the left knee joint. Measurement module6004 couples to lateral femoral support 6008. In one embodiment, thelateral compartment height can be raised or lowered under loading on thelateral side of the left knee joint by distraction mechanism 5014. Auser controls movement of the lateral support structure 5108 and therebylateral femoral support 6008. In the example, lateral tilting screw 5112couples to lateral support structure 5108 through cap 5062 of cagesystem 5011. The user can rotate lateral tilting screw 5112 with awrench where the rotation moves lateral support structure 5108 towardscap 5062 or away from cap 5062 depending on the direction of rotation.Alternatively, movement of distraction mechanism 5014 can be automatedsuch that the lateral compartment height is changed by motor, pneumatic,electrical, or other mechanical system without the need of a user incontact with surgical apparatus 6000. A measurement module 6004 couplesto lateral femoral support 6008. Lateral side loading of the left kneejoint is applied to measurement module 6008 and thereby lateral femoralsupport 6008. Measurement module 6004 is configured with at least onesensor to generate quantitative measurement data related to the leftknee joint. In one embodiment, measurement module 6004 measures loading,position of load, alignment, and balance. In one embodiment, measurementmodules 6002 and 6004 respectively measure and transmit measurement datato computer 5026 of FIG. 64. Thus, the medial compartment height and thelateral compartment of the left knee joint can be raised and loweredindependently through medial tilting screw 5110 and lateral tiltingscrew 5112 by the user whereas both the medial and lateral compartmentheights can be adjusted by raising or lowering tibial support 5006.

FIG. 66 is a top view of an offset of surgical apparatus 6000 for use ina right knee in accordance with an example embodiment. In the example,surgical apparatus 6000 comprises a right leg surgical apparatus 6052configured for supporting a right leg prosthetic knee jointinstallation. Right leg surgical apparatus 6052 has an offset thatsupports placing the patella to the one side of the knee joint whileright leg surgical apparatus 6052 is inserted. The patella can then beplaced back on the right knee joint with right leg surgical apparatus6052 in place due to the offset. Placing the patella on the knee jointwhile right leg surgical apparatus 6052 is being used loads the kneejoint as it would once the prosthetic knee joint has been installed.Thus, loading of the patella is taken into account in regards to legalignment, loading, and balance as right leg surgical apparatus 6052 isused to support a right leg prosthetic knee joint installation.

Tibial support 5006 of distraction mechanism 5010 couples to cage system5011 in a manner that allows movement of tibial support 5006 underloading of the right knee joint. In one embodiment, a user controlsmovement of tibial support 5006 using distraction mechanism 5010 suchthat a medial and a lateral compartment height of the left knee jointcan be changed. Alternatively, movement of distraction mechanism 5010can be automated such that the medial and lateral compartment height ischanged by motor, pneumatic, electrical, or other mechanical system. Ineither case, measurement data is provided to computer 5026 of FIG. 64for display and analysis.

Medial femoral support 6006 couples to medial support structure 5106.Medial support structure 5106 of distraction mechanism 5012 couples tocage system 5011 in a manner that allows movement of medial femoralsupport 6006 under loading of the left knee joint. Measurement module6002 couples to medial femoral support 6006. In one embodiment, themedial compartment height can be raised or lowered under loading on themedial side of the right knee joint by distraction mechanism 5012. Auser controls movement of the medial support structure 5106 and therebymedial femoral support 6006. In the example, medial tilting screw 5110couples to medial support structure 5106 through cap 5062 of cage system5011. The user can rotate medial tilting screw 5110 with a wrench wherethe rotation moves medial support structure 5106 towards cap 5062 oraway from cap 5062 depending on the direction of rotation.Alternatively, movement of distraction mechanism 5012 can be automatedsuch that the medial compartment height is changed by motor, pneumatic,electrical, or other mechanical system without the need of a user incontact with surgical apparatus 6000. A measurement module 6002 couplesto medial femoral support 6006. Medial side loading of the left kneejoint is applied to measurement module 6002 and thereby medial femoralsupport 6006. Measurement module 6002 is configured with at least onesensor to generate quantitative measurement data related to the leftknee joint. In one embodiment, measurement module 6002 measures loading,position of load, alignment, and balance. Screws 5080, 5082, 5084, and5086 hold cap 5062 to cage system 5011.

Lateral femoral support 6008 couples to lateral support structure 5108.Lateral support structure 5108 of distraction mechanism 5014 couples tocage system 5011 in a manner that allows movement of lateral femoralsupport 6006 under loading of the right knee joint. Measurement module6004 couples to lateral femoral support 6008. In one embodiment, thelateral compartment height can be raised or lowered under loading on thelateral side of the right knee joint by distraction mechanism 5014. Auser controls movement of the lateral support structure 5108 and therebylateral femoral support 6008. In the example, lateral tilting screw 5112couples to lateral support structure 5108 through cap 5062 of cagesystem 5011. The user can rotate lateral tilting screw 5112 with awrench where the rotation moves lateral support structure 5108 towardscap 5062 or away from cap 5062 depending on the direction of rotation.Alternatively, movement of distraction mechanism 5014 can be automatedsuch that the lateral compartment height is changed by motor, pneumatic,electrical, or other mechanical system without the need of a user incontact with surgical apparatus 6000. A measurement module 6004 couplesto lateral femoral support 6008. Lateral side loading of the right kneejoint is applied to measurement module 6008 and thereby lateral femoralsupport 6008. Measurement module 6004 is configured with at least onesensor to generate quantitative measurement data related to the rightknee joint. In one embodiment, measurement module 6004 measures loading,position of load, alignment, and balance. In one embodiment, measurementmodules 6002 and 6004 respectively measure and transmit measurement datato computer 5026 of FIG. 64. Thus, the medial compartment height and thelateral compartment of the right knee joint can be raised and loweredindependently through medial tilting screw 5110 and lateral tiltingscrew 5112 by the user whereas both the medial and lateral compartmentheights can be adjusted equally by raising or lowering tibial support5006. Note that the operation of left leg surgical apparatus 6050 andright leg surgical apparatus 6052 are identical. Thus, when discussingsurgical apparatus 6000 the description applies to both the left legsurgical apparatus 6050 and a right leg surgical apparatus 6052. In oneembodiment, left leg surgical apparatus 6050 and right leg surgicalapparatus 6052 are symmetrical about an anterior-posterior access.

FIG. 67 is an illustration of a surgical apparatus 6000 with a medialand a lateral compartment height in a minimum height position inaccordance with an example embodiment. In the example, medial femoralsupport 6006 and lateral femoral support 6008 are lowered to couple totibial support 5006. In one embodiment, the minimum height occurs whenthe bottom surface 5142 of tibial support 5006 is co-planar to bottomsurfaces 6070 and 6072 respectively of medial femoral support 6006 andlateral femoral support 6008. In one embodiment, the minimum heightcorresponds to a distance between bottom surface 5142 of tibial support5006 and a surface of measurement module 6002 and 6004 as indicated bydouble headed arrow 6020.

A process of placing surgical apparatus 6000 in the minimum heightposition comprises rotating medial tilting screw 5110 to move medialfemoral support 6006 towards base 5060 until medial support structure5106 couples to spacer block 5104. Lateral tilting screw 5112 is rotatedto move lateral femoral support 6008 towards base 5060 until lateralsupport structure 5108 couples to spacer block 5104. Handle 5094 isrotated to move tibial support 5006 towards cap 5062 until tibialsupport 5006 couples to medial femoral support 6006 and lateral femoralsupport 6008. No order is implied by these steps. Surgical apparatus6000 in the minimum height position is now configured to be insertedinto a knee joint. The minimum medial and lateral compartment heights ofsurgical apparatus 6000 is less than the height of the one or moreinserts that can be used in a final prosthetic knee joint. Onceinserted, surgical apparatus 6000 can be used to change the medial orlateral compartment heights to support installation of the prostheticknee joint by adjusting the distractor mechanisms. In one embodiment,surgical apparatus 6000 can distract the knee joint to compartmentheights corresponding to final inserts used in the prosthetic kneejoint.

A first cap and a second cap may respectively overlie measurement module6002 and measurement module 6004. The first cap and the second capprovides a surface to interface with the medial condyle and the lateralcondyles of the femur or condyles of the femoral prosthetic component.The first cap and the second cap distribute loading respectively to thesurface of measurement module 6002 and measurement module 6004. In oneembodiment, the first cap and the second cap can comprise a metal, ametal alloy, a polymer, or organic material. In one embodiment, thefirst cap and the second cap are rigid and does not flex. Alternatively,the first cap and the second cap can be designed to flex.

FIG. 68 is an illustration of surgical apparatus 6000 changing a heightof the medial and lateral compartments simultaneously in accordance withan example embodiment. The offset of surgical apparatus 6000 is for usein a left leg. All steps or actions disclosed herein can be performedfor surgical apparatus in a right leg or left leg configuration. In theexample, a surface of measurement module 6002 and a surface ofmeasurement module 6004 are co-planar. Although not shown, measurementmodule 6002 and measurement module 6004 would respectively couple to amedial condyle and a lateral condyle of a femur when inserted in theknee joint similar to that shown in FIG. 53. The medial or lateralcondyles can be natural condyles or condyles of a femoral prostheticcomponent. In the example, surgical apparatus 6000 is inserted into theknee joint with the medial and lateral compartments of surgicalapparatus 6000 at a minimum height. Tibial support 5006 couples to aproximal end of the tibia. The proximal end of the tibia can be eitherthe natural surface or a prepared surface of the tibia. In oneembodiment, surgical apparatus 6000 is inserted into the knee joint withthe leg in extension. Once inserted, the medial compartment heightcorresponds to the distance from the surface of measurement module 6002to bottom surface 5142 of tibial support 5006. Likewise, the lateralcompartment height corresponds to the distance from the surface ofmeasurement module 6004 to bottom surface 5142 of tibial support 5006.In the example, the medial and lateral compartments of surgicalapparatus 6000 have been set to the minimum height prior to insertion.Once inserted, surgical apparatus the medial and lateral compartmentswill be at least be distracted to the minimum height. Surgical apparatus6000 may be under load when inserted into the knee joint oralternatively the medial and lateral compartment heights may have to beincreased from the minimum height to be loaded by the knee joint.

Distraction mechanism 5010 moves tibial support 5006 towards base 5060or away from base 5060. Knob 5094 is coupled to distraction lead screw5092 which threads into a threaded opening of tibial support holder5088. Rotating knob 5094 engages threads of distraction lead screw 5092with the threads of tibial support holder 5088. In the example, knob5094 is rotated as indicated by arrow 6094 in a clockwise direction.Rotating knob 5094 clockwise moves tibial support holder 5088 towardsbase 5060 on a trajectory determined by cage system 5011 and therebyalso moving tibial support 5006 by the same distance. Note that movingtibial support 5006 changes the distance of both the medial and lateralcompartment heights simultaneously. In the example, the medialcompartment height is indicated by arrow 6090 which is the distance fromthe surface of measurement module 6002 to bottom surface 5142 of tibialsupport 5006. Similarly, the lateral compartment height is indicated byarrow 6092 which is the distance from the surface of measurement module6004 to bottom surface 5142 of tibial support 5006. The medial andlateral compartments have the same height after rotation of knob 5094because the surfaces of measurement modules 6002 and 6004 were co-planarto one another prior to rotation of knob 5094.

Conversely, the medial and lateral compartment heights can be decreasedby rotating knob 5094 counterclockwise which moves tibial support 5006away from base 5060. In one embodiment, knob 5094 cannot be rotated whenthe medial and lateral compartments are at the minimum height becausetibial support 5006 will be in contact with medial femoral support 6006and lateral femoral support 6008 thereby preventing further movement oftibial support 5006. In another example, assume that the medial andlateral compartments heights were different. Rotating knob 5094 willproduce an equal change in height for both the medial and lateralcompartments. For example, assume a medial compartment height of 11 cmand a lateral compartment height of 10 cm prior to rotation of knob5094. Knob 5094 is then rotated to move tibial support 5006 1.0centimeters away from base 5060. The medial compartment height would be10 cm and the lateral compartment height would be at 9 cm after rotationof knob 5094. Thus, the change in height affects both the medial andlateral compartments equally whether increasing or decreasing thecompartment heights with distraction mechanism 5010.

FIG. 69 is an illustration of surgical apparatus 6000 changing a heightof the medial compartment in accordance with an example embodiment. Theoffset of surgical apparatus 6000 is for use in a left leg. All steps oractions disclosed herein can be performed using surgical apparatus 6000for a right leg or left leg configuration. In the example, a surface ofmeasurement module 6002 and a surface of measurement module 6004 arenon-planar to one another. Although not shown, measurement module 6002and measurement module 6004 would respectively couple to a medialcondyle and a lateral condyle of a distal end of a femur similar to thatshown in FIG. 53. Tibial support 5006 is configured to couple to aproximal end of a tibia similar to that shown in FIG. 53. In oneembodiment, surgical apparatus 6000 is inserted into a left knee jointwith the leg in extension and adjusted to change the medial and lateralcompartment heights. The medial compartment height corresponds to thedistance from the surface of measurement module 6002 to bottom surface5142 of tibial support 5006 as indicated by arrow 6090. Likewise, thelateral compartment height corresponds to the distance from the surfaceof measurement module 6004 to bottom surface 5142 of tibial support 5006as indicated by arrow 6092. Surgical apparatus 6000 is configured tohave the medial and lateral compartments a minimum height of the device.Upon insertion, surgical apparatus 6000 distracts the knee joint to theminimum height. Surgical apparatus 6000 may be under load when insertedinto the knee joint or alternatively the medial and lateral compartmentheights may have to be increased from the minimum height to be loaded bythe knee joint.

Distraction mechanism 5010 is configured to move tibial support 5006such that the height of the medial and lateral compartments changes bythe same amount. Knob 5094 is coupled to distraction lead screw 5092which threads into tibial support holder 5088. Rotating knob 5094engages threads of distraction lead screw 5092 with the threads oftibial support holder 5088. In the example, knob 5094 is rotated in aclockwise direction to change the height of the medial and lateralcompartment from the minimum height to a first predetermined height.Rotating knob 5094 clockwise moves tibial support holder 5088 towardsbase 5060 on a trajectory determined by cage system 5011 and therebyalso moving tibial support 5006 by the same distance. Note that movingtibial support 5006 changes the medial and lateral compartment heightssimultaneously. Conversely, rotating knob 5094 counter-clockwise wouldmove tibial support 5006 away from base 5060 thereby reducing the medialand lateral compartment heights by the same amount. Although not shown,both the medial and lateral compartment heights would be at the firstpredetermined height as indicated by arrow 6092 corresponding to thelateral compartment height in this intermediate step.

Distraction mechanism 5012 is then used to change the medial compartmentheight. In the example, the medial compartment height is furtheradjusted by rotating medial tilt screw 5110 in a clockwise direction asindicated by arrow 6094. Rotating medial tilt screw 5110 clockwise movesmedial femoral support 6006 towards cap 5062 to increase the medialcompartment height to a second predetermined height. In the example, thesecond predetermined height of the medial compartment is indicated byarrow 6090. Conversely, rotating medial tilt screw 5110 counterclockwisemoves femoral support 6006 away from cap 5062 to reduce the medialcompartment height. Note that the height of the lateral compartment doesnot change as medial tilt screw 5110 is rotated only the medialcompartment height is changed. There is no order implied by the stepsdisclosed. For example, distraction mechanism 5012 could be adjustedfollowed by adjusting distraction mechanism 5010.

Distraction mechanism 5014 is not adjusted in the example. Thus, thelateral compartment height remains at the first predetermined height.The lateral compartment height is indicated by arrow 6092. As mentionedpreviously, surgical apparatus 6000 is inserted with the medial andlateral compartments at the minimum height. Increasing the medial andlateral compartment heights using distraction mechanism 5010 will loadmeasurement modules 6002 and 6004 in the knee joint. Increasing theheight of the medial compartment with distraction mechanism 5012 willfurther increase the loading on the medial compartment. In oneembodiment, sensors in measurement module 6002 and 6004 provide loadmeasurement data to computer 5026 of FIG. 67. Sensors or mechanicalgauges in or on surgical apparatus 6000 provide measurement data relatedto tilt and height of the medial and lateral compartment. Computer 5026can provide the measurement data in a visual, audible, or haptic mannerthat allows the user to rapidly assimilate the information duringsurgery. Computer 5026 can include one or more software programs thatsupport the knee installation and utilize the measurement data inreal-time to provide a surgical workflow and one or more options tooptimize the procedure. In one embodiment, the measurement data andcomputer 5026 can provide information relating to the balance betweenmedial and lateral compartments, the height of the medial or lateralcompartments, the medial-lateral tilt, alignment of the femur, alignmentof the tibia, alignment relative to the contact points on modules 6002and 6004 where the medial and lateral condyles touch measurement modules6002 and 6004, a load magnitude applied by the medial or lateralcondyles to modules 6002 and 6004.

FIG. 70 is an illustration of surgical apparatus 6000 changing a heightof the lateral compartment in accordance with an example embodiment. Theoffset of surgical apparatus 6000 is for use in a left leg in theexample. All steps or actions disclosed herein can be performed usingsurgical apparatus 6000 for a right leg or left leg configuration. Inthe example, a surface of measurement module 6002 and a surface ofmeasurement module 6004 are non-planar to one another. Although notshown, measurement module 6002 and measurement module 6004 wouldrespectively couple to a medial condyle and a lateral condyle of adistal end of a femur similar to that shown in FIG. 53. Surgicalapparatus 6000 can couple to a natural, prepared, or prostheticcomponent at the distal end of the femur. Tibial support 5006 isconfigured to couple to a proximal end of a tibia similar to that shownin FIG. 53. Similarly, surgical apparatus 6000 can couple to a natural,prepared, or prosthetic component at the proximal end of the tibia. Inone embodiment, surgical apparatus 6000 is inserted into a left kneejoint with the leg in extension and adjusted to change the medial andlateral compartment heights. The medial compartment height correspondsto the distance from the surface of measurement module 6002 to bottomsurface 5142 of tibial support 5006 as indicated by arrow 6090.Likewise, the lateral compartment height corresponds to the distancefrom the surface of measurement module 6004 to bottom surface 5142 oftibial support 5006 as indicated by arrow 6092. In one embodiment,surgical apparatus 6000 is configured to have the medial and lateralcompartments at the minimum height of the device prior to insertion.Upon insertion, surgical apparatus 6000 distracts the knee joint to theminimum height. Surgical apparatus 6000 may be under load when insertedinto the knee joint or alternatively the medial and lateral compartmentheights may have to be increased from the minimum height to be loaded bythe knee joint.

Distraction mechanism 5010 is configured to move tibial support 5006such that the height of the medial and lateral compartments changes bythe same amount. Knob 5094 is coupled to distraction lead screw 5092which threads into tibial support holder 5088. Rotating knob 5094engages threads of distraction lead screw 5092 with the threads oftibial support holder 5088. In the example, knob 5094 is rotated in aclockwise direction to change the height of the medial and lateralcompartment from the minimum height to a first predetermined height.Rotating knob 5094 clockwise moves tibial support holder 5088 towardsbase 5060 on a trajectory determined by cage system 5011 and therebyalso moving tibial support 5006 by the same distance. Note that movingtibial support 5006 changes the medial and lateral compartment heightssimultaneously. Conversely, rotating knob 5094 counter-clockwise wouldmove tibial support 5006 away from base 5060 thereby reducing the medialand lateral compartment heights by the same amount. Although not shown,both the medial and lateral compartment heights would be at the firstpredetermined height as indicated by arrow 6090 corresponding to themedial compartment height in this intermediate step.

Distraction mechanism 5014 is then used to change the lateralcompartment height. In the example, the lateral compartment height isfurther adjusted by rotating lateral tilt screw 5112 in a clockwisedirection as indicated by arrow 6094. Rotating lateral tilt screw 5112clockwise moves lateral femoral support 6008 towards cap 5062 toincrease the lateral compartment height to a second predeterminedheight. In the example, the second predetermined height of the lateralcompartment is indicated by arrow 6092. Conversely, rotating lateraltilt screw 5112 counterclockwise moves femoral support 6008 away fromcap 5062 to reduce the lateral compartment height. Note that the heightof the medial compartment does not change as lateral tilt screw 5112 isrotated; only the lateral compartment height is changed. There is noorder implied by the steps disclosed. For example, distraction mechanism5014 could be adjusted followed by adjusting distraction mechanism 5010.

Distraction mechanism 5012 is not adjusted in the example. Thus, themedial compartment height remains at the first predetermined height. Themedial compartment height is indicated by arrow 6090. As mentionedpreviously, surgical apparatus 6000 is inserted with the medial andlateral compartments at the minimum height. Increasing the medial andlateral compartment heights using distraction mechanism 5010 will loadmeasurement modules 6002 and 6004 in the knee joint. Increasing theheight of the lateral compartment with distraction mechanism 5014 willfurther increase the loading on the lateral compartment. In oneembodiment, sensors in measurement module 6002 and 6004 provide loadmeasurement data to computer 5026 of FIG. 67. Sensors or mechanicalgauges in or on surgical apparatus 6000 provide measurement data relatedto tilt and height of the medial and lateral compartment. Computer 5026can provide the measurement data in a visual, audible, or haptic mannerthat allows the user to rapidly assimilate the information duringsurgery. Computer 5026 can include one or more software programs thatsupport the knee installation and utilize the measurement data inreal-time to provide a surgical workflow and one or more options tooptimize the procedure. In one embodiment, the measurement data andcomputer 5026 can provide information relating to the balance betweenmedial and lateral compartments, the height of the medial or lateralcompartments, the medial-lateral tilt, alignment of the femur, alignmentof the tibia, alignment relative to the contact points on modules 6002and 6004 where the medial and lateral condyles touch measurement modules6002 and 6004, a load magnitude applied by the medial or lateralcondyles to modules 6002 and 6004.

It should be noted that very little data exists on implanted orthopedicdevices. Most of the data is empirically obtained by analyzingorthopedic devices that have been used in a human subject or simulateduse. Wear patterns, material issues, and failure mechanisms are studied.Although, information can be garnered through this type of study it doesyield substantive data about the initial installation, post-operativeuse, and long term use from a measurement perspective. Just as eachperson is different, each device installation is different havingvariations in initial loading, balance, and alignment. Having measureddata and using the data to install an orthopedic device will greatlyincrease the consistency of the implant procedure thereby reducingrework and maximizing the life of the device. In at least one exemplaryembodiment, the measured data can be collected to a database where itcan be stored and analyzed. For example, once a relevant sample of themeasured data is collected, it can be used to define optimal initialmeasured settings, geometries, and alignments for maximizing the lifeand usability of an implanted orthopedic device.

The present invention is applicable to a wide range of medical andnonmedical applications including, but not limited to, frequencycompensation; control of, or alarms for, physical systems; or monitoringor measuring physical parameters of interest. The level of accuracy andrepeatability attainable in a highly compact sensing module or surgicalapparatus may be applicable to many medical applications monitoring ormeasuring physiological parameters throughout the human body including,not limited to, bone density, movement, viscosity, and pressure ofvarious fluids, localized temperature, etc. with applications in thevascular, lymph, respiratory, digestive system, muscles, bones, andjoints, other soft tissue areas, and interstitial fluids.

While the present invention has been described with reference toparticular embodiments, those skilled in the art will recognize thatmany changes may be made thereto without departing from the spirit andscope of the present invention. Each of these embodiments and obviousvariations thereof is contemplated as falling within the spirit andscope of the invention.

What is claimed is:
 1. A surgical apparatus configured to support atleast one bone cut comprising: a first support structure configured tocouple to a first bone of a musculoskeletal system; a second supportstructure configured to couple to a second bone of the musculoskeletalsystem wherein the surgical apparatus is configured to increase ordecrease a height between the first support structure and the secondsupport structure, wherein the second support structure is configured totilt under user control, wherein the second support structure isconfigured to tilt through a first pivot point and a second pivot point,and wherein loading applied to the second support structure isdistributed between the first and second pivot points; a seconddistraction mechanism configured to couple to the second supportstructure wherein the second distraction mechanism is configured tochange a distance between a first side of the second support structureand the first support structure, and a third distraction mechanismconfigured to couple to the second support structure wherein the thirddistraction mechanism is configured to change a distance between asecond side of the second support structure and the first supportstructure, wherein the first pivot point comprises a first cylindricalpin extending from the second support structure configured to couple toa first cylindrical opening in the surgical apparatus and wherein thesecond pivot point comprises a second cylindrical pin extending from thesecond support structure configured to couple to a second cylindricalopening in the surgical apparatus, wherein at least one load sensoroverlies the first side of the second support structure, wherein the atleast one load sensor is configured to measure loading applied to thefirst side by the musculoskeletal system, wherein at least one loadsensor overlies the second side of the second support structure, whereinthe at least one load sensor is configured to measure loading applied tothe second side by the musculoskeletal system.
 2. The surgical apparatusof claim 1 wherein the second support structure has a first side and asecond side, wherein the first cylindrical pin is configured to supportthe first side of the second support structure, and wherein the secondcylindrical pin is configured to support the second side of the secondsupport structure.
 3. The surgical apparatus of claim 1 furtherincluding a first distraction mechanism coupled to the first supportstructure wherein the first distraction mechanism is configured tochange a distance between the first and second support structures byequal amounts.
 4. The surgical apparatus of claim 3 wherein the computerdisplays a tilt meter configured to graphically display tilt.
 5. Thesurgical apparatus of claim 1 further including a computer having adisplay configured to receive quantitative measurement data from thesurgical apparatus wherein the display is in view of the surgical team,wherein the surgical apparatus includes at least one sensor configuredto measure tilt of the second support structure, and wherein the displayof the computer displays the tilt of the second support structure inreal-time.
 6. The surgical apparatus of claim 1 wherein the surgicalapparatus is configured to be inserted into the musculoskeletal system,the musculoskeletal system being in a first pose, wherein the surgicalapparatus is adjustable from a first position to a second position underuser control, wherein in the first position the surgical apparatus isconfigured to distract the musculoskeletal system to a firstpredetermined height and a first tilt under user control, wherein in thesecond position the surgical apparatus is configured to be adjusted to asecond tilt under user control, and wherein the second tilt isconfigured to be related to a first bone cut to the first bone or secondbone to support installation of a prosthetic component.
 7. The surgicalapparatus of claim 6 wherein the surgical apparatus is configured to beinserted into the musculoskeletal system, the musculoskeletal systembeing in a second pose, wherein the surgical apparatus is adjustablefrom a third position to a fourth position under user control, whereinin the third position the surgical apparatus is configured to distractthe musculoskeletal system to a first third predetermined height and athird tilt in the second pose under user control, wherein in the fourthposition the surgical apparatus is configured to be adjusted to a fourthtilt in the second pose under user control, and wherein the fourth tiltin the second pose is configured to be related to a second bone cut tothe first bone or second bone to support installation of a prostheticcomponent.
 8. A surgical apparatus configured to support at least onebone cut comprising: a first support structure configured to couple to afirst bone of a musculoskeletal system; a second support structureconfigured to couple to a second bone of the musculoskeletal systemwherein the second support structure has a first side and a second side,wherein the surgical apparatus is configured to increase or decrease aheight between the first support structure and the second supportstructure, wherein the second support structure is configured to tiltunder user control, wherein the second support structure is configuredto tilt through a first pivot point and a second pivot point, andwherein loading applied to the second support structure is distributedbetween the first and second pivot points, a first distraction mechanismcoupled to the first support structure wherein the first distractionmechanism is configured to change a distance between the first andsecond support structures by equal amounts; a second distractionmechanism configured to couple to the second support structure whereinthe second distraction mechanism is configured to change a distancebetween the medial side of the second support structure and the firstsupport structure; a third distraction mechanism configured to couple tothe second support structure wherein the third distraction mechanism isconfigured to change a distance between a lateral side of the secondsupport structure and the first support structure; at least one sensorconfigured to measure tilt of the second support structure; at least oneload sensor overlying the first side of the second support structureconfigured; and at least one load sensor overlying the second side ofthe second support structure.
 9. The surgical apparatus of claim 8further including a computer having a display configured to receivequantitative measurement data from the surgical apparatus wherein thedisplay of the computer displays the tilt of the second supportstructure in real-time.
 10. The surgical apparatus of claim 8 whereinthe surgical apparatus is configured to be inserted into themusculoskeletal system, the musculoskeletal system being in a firstpose, wherein the surgical apparatus is adjustable from a first positionto a second position under user control, wherein in the first positionthe surgical apparatus is configured to distract the musculoskeletalsystem to a first predetermined height and a first tilt under usercontrol, wherein the surgical apparatus in the second position isconfigured to be adjusted to a second tilt under user control, andwherein the second tilt is configured to be related to a first bone cutto the first bone or second bone to support installation of a prostheticcomponent.
 11. The surgical apparatus of claim 10 wherein the surgicalapparatus is configured to be inserted into the musculoskeletal system,the musculoskeletal system being in a second pose, wherein the surgicalapparatus is adjustable from a third position to a fourth position underuser control, wherein in the third position the surgical apparatus isconfigured to distract the musculoskeletal system to a thirdpredetermined height and a third tilt in the second pose under usercontrol, wherein in the fourth position the surgical apparatus isconfigured to be adjusted to a fourth tilt in the second pose under usercontrol, and wherein the fourth tilt in the second pose is configured tobe related to a second bone cut to the first bone or second bone tosupport installation of a prosthetic component.
 12. A surgical apparatusconfigured to support at least one bone cut comprising: a first supportstructure configured to couple to a tibia of a musculoskeletal system; asecond support structure configured to couple to a femur of themusculoskeletal system wherein the second support structure has a medialside and a lateral side, wherein the surgical apparatus is configured toincrease or decrease a height between the first support structure andthe second support structure, wherein the second support structure isconfigured to tilt under user control, wherein the second supportstructure is configured to tilt through a first pivot point and a secondpivot point, and wherein loading applied to the second support structureis distributed between the first and second pivot points; a firstdistraction mechanism coupled to the first support structure wherein thefirst distraction mechanism is configured to change a distance betweenthe first and second support structures by equal amounts; a seconddistraction mechanism configured to couple to the second supportstructure wherein the second distraction mechanism is configured tochange a distance between the medial side of the second supportstructure and the first support structure; a third distraction mechanismconfigured to couple to the second support structure wherein the thirddistraction mechanism is configured to change a distance between alateral side of the second support structure and the first supportstructure wherein at least one load sensor overlies the medial side ofthe second support structure, wherein the at least one load sensoroverlying the medial side is configured to measure loading applied tothe medial side by the musculoskeletal system, wherein at least one loadsensor overlies the lateral side of the second support structure,wherein the at least one load sensor overlying the lateral side isconfigured to measure loading applied to the lateral side by themusculoskeletal system, and a computer having a display configured toreceive quantitative measurement data from the surgical apparatuswherein the display is in view of the surgical team, wherein thesurgical apparatus includes at least one sensor configured to measuretilt of the second support structure, and wherein the display of thecomputer displays the tilt of the second support structure in real-time.13. The surgical apparatus of claim 12 wherein the computer displays atilt meter configured to graphically display tilt.
 14. The surgicalapparatus of claim 12 wherein the surgical apparatus is configured to beinserted between the tibia and the femur of a leg in a first pose,wherein the surgical apparatus is adjustable from a first position to asecond position under user control, wherein in the first position thesurgical apparatus is configured to distract the musculoskeletal systemto a first predetermined height and a first tilt under user control,wherein the surgical apparatus in the second position is configured tobe adjusted to a second tilt under user control, and wherein the secondtilt is configured to be related to a first bone cut to the femur ortibia to support installation of a prosthetic component.